Adjusting Kelvin tickover

[MtB]

My K1 seems to tick over these days at about 220rpm. It's supposed to be 160rpm as I understand it. I'm reasonably sure it used to be 160rpm when I first installed it so I'm wondering what has changed.

 

What is the correct way to set the tickover speed? The obvious way - adjusting the throttle lever travel end stop - doesn't work. The stop is already at the end of it's adustment at the lower speed end of travel

 

The spring at the end of the chain and rod assembly that passes through the fuel pump and governor is attached to a peg with a bendy bit of wire (looks like the 'S' hook from a wc cistern) which has clearly been bent many times to ajust it's length and consequently the tension on the spring. I've found that unhooking it and reducing the spring tension by hand reduces the tickover speed but is changing the spring tension an appropriate way to adjust tickover? Or does modifying the spring tension actually change something throughout the whole rev range, with tickover speed change being a by-product of the adjustment, meaning I should not be fiddling with the spring tension?

 

Any suggestions please?

 

Many thanks,

Mike

[NB Alnwick]

I cannot remember which governor you have but both variants of the Kelvin 'J'/'K' governor operate hydraulically on diesel fuel which needs to be topped up before starting. The only way to adjust minimum and maximum engine speed, is by adjusting the sliding stops that restrict the minimum and maximum position of the governor speed lever. The sliding stops are adjusted by slackening the 1/4 BSF hex head screw, setting the slide to the correct position and re-tightening the screw. At each end, there should be a choice of two or three 1/4 BSF tapped holes for the sliding stop screws - these enable additional adjustment that may beyond the limit of the slot in the sliding stops.

 

Whatever you do, do not alter the temper of the spring or the position of the stop on the injection pump rack.

 

It is quite normal for the engine to idle a bit faster when it gets very hot but I think 220 is on the fast side.

 

A final thought which may have far more relevance than what I have said above: The governors fitted to Kelvin 'J' series engines were designed to give an engine speed range of between 225 and 1000 rpm (compared with 160 to 750 rpm on the 'K' series) - is it possible that you have a 'J' series governor fitted?

[rjasmith]

My K1 seems to tick over these days at about 220rpm. It's supposed to be 160rpm as I understand it. I'm reasonably sure it used to be 160rpm when I first installed it so I'm wondering what has changed.

 

What is the correct way to set the tickover speed? The obvious way - adjusting the throttle lever travel end stop - doesn't work. The stop is already at the end of it's adustment at the lower speed end of travel

 

The spring at the end of the chain and rod assembly that passes through the fuel pump and governor is attached to a peg with a bendy bit of wire (looks like the 'S' hook from a wc cistern) which has clearly been bent many times to ajust it's length and consequently the tension on the spring. I've found that unhooking it and reducing the spring tension by hand reduces the tickover speed but is changing the spring tension an appropriate way to adjust tickover? Or does modifying the spring tension actually change something throughout the whole rev range, with tickover speed change being a by-product of the adjustment, meaning I should not be fiddling with the spring tension?

 

Any suggestions please?

 

Many thanks,

Mike

 

Mike,

 

Just a thought but have you checked that the fuel oil is being maintained at the correct level in the governor by the injector leak off pipe? Perhaps you could try draining all the fuel in the governor out (there's a drain screw on it) and then refill to the test cock level with clean fuel again. (The book does say the oil should be changed occasionally but I can't remember the interval - hasn't the governor got one of those helpful little plates saying this on it?)

 

I don't have experience of running my engine with a low governor oil level but as the governor relies on the fuel viscosity for its hydraulic governing action it's something that I would think might affect the governor's ability to slow down the speed by opposing the action of the spring trying to speed it up.

 

Richard

[MtB]

I cannot remember which governor you have but both variants of the Kelvin 'J'/'K' governor operate hydraulically on diesel fuel which needs to be topped up before starting. The only way to adjust minimum and maximum engine speed, is by adjusting the sliding stops that restrict the minimum and maximum position of the governor speed lever. The sliding stops are adjusted by slackening the 1/4 BSF hex head screw, setting the slide to the correct position and re-tightening the screw. At each end, there should be a choice of two or three 1/4 BSF tapped holes for the sliding stop screws - these enable additional adjustment that may beyond the limit of the slot in the sliding stops.

 

Whatever you do, do not alter the temper of the spring or the position of the stop on the injection pump rack.

 

It is quite normal for the engine to idle a bit faster when it gets very hot but I think 220 is on the fast side.

 

A final thought which may have far more relevance than what I have said above: The governors fitted to Kelvin 'J' series engines were designed to give an engine speed range of between 225 and 1000 rpm (compared with 160 to 750 rpm on the 'K' series) - is it possible that you have a 'J' series governor fitted?

 

Graham & Richard,

 

Thanks for your replies. I dunno which governor we have. I'll fish out a photo later.

 

I never top it up with oil. I've always assumed it is full because the overflow drain drips slowly but continuously and fills up the little dish I have arranged to catch the discharged diesel every few days.

 

I won't mess about with the spring then. I know just enough about combustion to see the potential for screwing it up!

 

I've found the throttle lever stops and the slow stop is adjusted to minimum, but it did not occur to me to see if there was another threaded hole to move to bolt into for more adjustment. I'll check this afternoon.

 

Re the possibility of having a J governor, how would I tell? My governor is definitely different from other K governors I've seen. I'll post a photo.

 

Time to start learing how the governor works I think...!

 

Cheers, Mike

Edited May 23, 2011 by Mike the Boilerman

[MtB]

A final thought which may have far more relevance than what I have said above: The governors fitted to Kelvin 'J' series engines were designed to give an engine speed range of between 225 and 1000 rpm (compared with 160 to 750 rpm on the 'K' series) - is it possible that you have a 'J' series governor fitted?

 

I'm not sure of the difference between a 'J' and a 'K' series governor, or of the difference between the two types of 'K' governor you mention. I took some photos of mine yesterday. They are 2mb each so rather than embed them directly in this post, here are links:

 

K1 governor

 

Brass label on governor

 

I checked the oil level in the governor. The test cock it blocked but the little bit of oil I added flowed straight back out the overflow pipe so the level is good. Too high really, as the overflow is 3/4" higher than the test cock. I don't suppose that would affect tickover would it? I don't understand how a governor works yet. I doubt it is a 'J' governor though as it used to tick over at 160rpm exactly. Something has changed since last year.

 

I have never drained and re-filled the governor as instructed on the brass label fixed to it though (and which I would not have noticed had Richard not pointed it out). I see the label also says "adjust according to instruction book" so I'm off now to see what the instruction book says!

 

( And by the way Graham, I submitted an advert for a wooden/interesting/historic narrowboat wanted on the For sale/Wanted board on Saturday but it seems to be still waiting approval by moderators. Any chance of checking it for me please?! Many thanks.)

 

Mike

[MoominPapa]

I submitted an advert for a .....historic narrowboat wanted on the For sale/Wanted board on Saturday.

 

You too? It's spreading like a rash around here! Owners of perfectly good modern narrowboats suddenly getting the hots for round chines and iron plates.......

 

 

<wanders off, mumbling to himself>

 

MP.

[MtB]

You too? It's spreading like a rash around here! Owners of perfectly good modern narrowboats suddenly getting the hots for round chines and iron plates.......

 

 

<wanders off, mumbling to himself>

 

MP.

 

I thought I was the one who started it all off actually, with this thread here:

 

Goliath

 

 

Mike

[rjasmith]

I'm not sure of the difference between a 'J' and a 'K' series governor, or of the difference between the two types of 'K' governor you mention. I took some photos of mine yesterday. They are 2mb each so rather than embed them directly in this post, here are links:

 

K1 governor

 

Brass label on governor

 

I checked the oil level in the governor. The test cock it blocked but the little bit of oil I added flowed straight back out the overflow pipe so the level is good. Too high really, as the overflow is 3/4" higher than the test cock. I don't suppose that would affect tickover would it? I don't understand how a governor works yet. I doubt it is a 'J' governor though as it used to tick over at 160rpm exactly. Something has changed since last year.

 

I have never drained and re-filled the governor as instructed on the brass label fixed to it though (and which I would not have noticed had Richard not pointed it out). I see the label also says "adjust according to instruction book" so I'm off now to see what the instruction book says!

 

( And by the way Graham, I submitted an advert for a wooden/interesting/historic narrowboat wanted on the For sale/Wanted board on Saturday but it seems to be still waiting approval by moderators. Any chance of checking it for me please?! Many thanks.)

 

Mike

 

Mike,

 

Here is my explanation of the way the governor works (total surmise - no real knowledge but it may draw out the greater experts if I've got it wrong!). You will get a clue if you study the parts drawing for the K engine on Mike Skyner's site.

 

The governor clearly has a gear pump exactly like the oil pump in a car (well traditional car anyway - it's probably done by electronics now for all I know!). This pressurises the hydraulic fluid (aka injector leak off diesel!) and this travels through drillings to the back of a piston in a cylinder which pulls on the injector pump control rack rod (via the bit of bike chain). The fluid in the cylinder also has access to an "exhaust port" which is varied in size by a valve controlled by the speed control lever. the output from the valve returns to the governor "sump" to go round again.

 

In this way, as the engine speeds up the gear pump produces more pressure, the piston pulls harder on the rack rod against the big spring at the other end and cuts the fuel to the injector enough to control the increase in engine speed. Similarly, if you alter the speed lever you vary the amount of fluid lost through the exhaust port and therefore the piston moves and the engine speed increases or decreases accordingly.

 

Now lets see if anyone shoots me down!!

 

I've just looked at your pics and it looks to me like you have the later type K governor that is excactly the same as mine. The earlier one was a splendid thing made of gunmetal with a lift up lid on the top to check/refill it rather than the little brass plug we have. The old one looks to me reminiscent of an arabic coffee pot (goes with the shape of the teapot aka carburetter)!!

 

I would certainly drain it out and replace the diesel to make sure it has clean stuff in there I wonder if this is why it has changed in operation over time - perhaps it's got the diesel bug!

 

Richard

[NB Alnwick]

Mike,

 

Here is my explanation of the way the governor works (total surmise - no real knowledge but it may draw out the greater experts if I've got it wrong!). You will get a clue if you study the parts drawing for the K engine on Mike Skyner's site.

 

The governor clearly has a gear pump exactly like the oil pump in a car (well traditional car anyway - it's probably done by electronics now for all I know!). This pressurises the hydraulic fluid (aka injector leak off diesel!) and this travels through drillings to the back of a piston in a cylinder which pulls on the injector pump control rack rod (via the bit of bike chain). The fluid in the cylinder also has access to an "exhaust port" which is varied in size by a valve controlled by the speed control lever. the output from the valve returns to the governor "sump" to go round again.

 

In this way, as the engine speeds up the gear pump produces more pressure, the piston pulls harder on the rack rod against the big spring at the other end and cuts the fuel to the injector enough to control the increase in engine speed. Similarly, if you alter the speed lever you vary the amount of fluid lost through the exhaust port and therefore the piston moves and the engine speed increases or decreases accordingly.

 

Now lets see if anyone shoots me down!!

 

I've just looked at your pics and it looks to me like you have the later type K governor that is excactly the same as mine. The earlier one was a splendid thing made of gunmetal with a lift up lid on the top to check/refill it rather than the little brass plug we have. The old one looks to me reminiscent of an arabic coffee pot (goes with the shape of the teapot aka carburetter)!!

 

I would certainly drain it out and replace the diesel to make sure it has clean stuff in there I wonder if this is why it has changed in operation over time - perhaps it's got the diesel bug!

 

Richard

 

I cannot improve on Richard's explanation! The governor fitted to most 'J' series engines looks the same externally but I believe there are internal differences - I may be wrong but I am sure they had different part numbers.

 

An old trick that can be used to slow the engine down (this only works with hydraulic governors) is to add some thick lubricating oil to the governor. If a governor has a percentage of lubricating oil in it, it will make the engine run much slower - especially when the ambient temperature is lower.

 

We have removed the low speed limit from our governor - this enables us to 'stall' the engine with the speed lever, whenever we need to stop it from the steering position. The next modification is to set up a spring-loaded stop so that we can 'feel' the correct slow running position on the speed lever.

[RLWP]

<snip>

We have removed the low speed limit from our governor - this enables us to 'stall' the engine with the speed lever, whenever we need to stop it from the steering position.

 

It's good for catching out the unwary too

 

Richard

 

[Timleech]

I cannot improve on Richard's explanation! The governor fitted to most 'J' series engines looks the same externally but I believe there are internal differences - I may be wrong but I am sure they had different part numbers.

 

An old trick that can be used to slow the engine down (this only works with hydraulic governors) is to add some thick lubricating oil to the governor. If a governor has a percentage of lubricating oil in it, it will make the engine run much slower - especially when the ambient temperature is lower.

 

We have removed the low speed limit from our governor - this enables us to 'stall' the engine with the speed lever, whenever we need to stop it from the steering position. The next modification is to set up a spring-loaded stop so that we can 'feel' the correct slow running position on the speed lever.

 

I reckon adding a percentage of lube oil is probably a good idea anyway. The early T engines used a very similar governor, they do wear over time, a bit of oil should help minimise the wear.

 

Tim

[MtB]

Mike,

 

Here is my explanation of the way the governor works (total surmise - no real knowledge but it may draw out the greater experts if I've got it wrong!). You will get a clue if you study the parts drawing for the K engine on Mike Skyner's site.

 

The governor clearly has a gear pump exactly like the oil pump in a car (well traditional car anyway - it's probably done by electronics now for all I know!). This pressurises the hydraulic fluid (aka injector leak off diesel!) and this travels through drillings to the back of a piston in a cylinder which pulls on the injector pump control rack rod (via the bit of bike chain). The fluid in the cylinder also has access to an "exhaust port" which is varied in size by a valve controlled by the speed control lever. the output from the valve returns to the governor "sump" to go round again.

 

In this way, as the engine speeds up the gear pump produces more pressure, the piston pulls harder on the rack rod against the big spring at the other end and cuts the fuel to the injector enough to control the increase in engine speed. Similarly, if you alter the speed lever you vary the amount of fluid lost through the exhaust port and therefore the piston moves and the engine speed increases or decreases accordingly.

 

Now lets see if anyone shoots me down!!

 

I've just looked at your pics and it looks to me like you have the later type K governor that is excactly the same as mine. The earlier one was a splendid thing made of gunmetal with a lift up lid on the top to check/refill it rather than the little brass plug we have. The old one looks to me reminiscent of an arabic coffee pot (goes with the shape of the teapot aka carburetter)!!

 

I would certainly drain it out and replace the diesel to make sure it has clean stuff in there I wonder if this is why it has changed in operation over time - perhaps it's got the diesel bug!

 

Richard

 

Richard,

 

Thanks for the detailed explanation. Much appreciated.

 

Now for the inevitable questions... ;-)

 

I can't see any parts breakdown of the governor proper on Mike Skyner's site. Only the peripheral components. Maybe I'm looking in the wrong place. I'm looking at this page http://www.sky-net.org.uk/kelvin/diesel/k_range/k_parts_list/index.html in the section headed "Governor Group". Is that where you meant? Or is there a proper breakdown showing the governor components somewhere else on the site I haven't found yet?

 

I imagine the "exhaust port" in the cylinder you mention is tapered in shape and partly obscured by the piston itself in such a way that the further the piston moves the bigger the 'visible' port area becomes, moderating the increase in piston pressure against the spring as engine speed and piston travel increases. Otherwise once a certain oil pressure is reached surely the piston would be pushed right out of the cylinder, wouldn't it? (Or maybe not as the spring resistance also increases as deflection rises.)

 

What does the rack rod do when it moves through the fuel pump? I imagine it increases or decreases the fuel charge sent to the injector and thereby varies the engine speed. If this is all, why would fiddling with the spring tension be such a Bad Thing? Surely all that would happen is the engine speed varies a little for a given throttle lever position. Or the rate of change of speed would change for a given throttle position change. Or something :-)

 

Anyway yes I'll try draining out the old diesel from it and adding new. I'll fix the test cock and maybe add some lubricating oil to the fluid. Thinking aloud, lube oil in the fluid will increase the viscosity and therefore raise the piston deflection for a given engine speed, leading to reduced injection volume and a slower engine speed after all. Hmmm I think I see. In fact I think it's more likely that the governor oil was originally part oil part diesel and having had a litre or so of diesel come out of the drain now, the oil/diesel mix has all gone and been replaced with pure diesel which is why the tickover has risen slowly over the months! What do you think?

 

I'll report the results of adding oil in a while.... I'm off out to look at boats for sale tomorrow!

 

In the meantime I've made some progress on the petrol running problem. Or rather I haven't. I'll resurrect that thread with an update soon :-)

 

Mike

[rjasmith]

Richard,

 

Thanks for the detailed explanation. Much appreciated.

 

Now for the inevitable questions... ;-)

 

I can't see any parts breakdown of the governor proper on Mike Skyner's site. Only the peripheral components. Maybe I'm looking in the wrong place. I'm looking at this page http://www.sky-net.org.uk/kelvin/diesel/k_range/k_parts_list/index.html in the section headed "Governor Group". Is that where you meant? Or is there a proper breakdown showing the governor components somewhere else on the site I haven't found yet?

 

I imagine the "exhaust port" in the cylinder you mention is tapered in shape and partly obscured by the piston itself in such a way that the further the piston moves the bigger the 'visible' port area becomes, moderating the increase in piston pressure against the spring as engine speed and piston travel increases. Otherwise once a certain oil pressure is reached surely the piston would be pushed right out of the cylinder, wouldn't it? (Or maybe not as the spring resistance also increases as deflection rises.)

 

What does the rack rod do when it moves through the fuel pump? I imagine it increases or decreases the fuel charge sent to the injector and thereby varies the engine speed. If this is all, why would fiddling with the spring tension be such a Bad Thing? Surely all that would happen is the engine speed varies a little for a given throttle lever position. Or the rate of change of speed would change for a given throttle position change. Or something :-)

 

Anyway yes I'll try draining out the old diesel from it and adding new. I'll fix the test cock and maybe add some lubricating oil to the fluid. Thinking aloud, lube oil in the fluid will increase the viscosity and therefore raise the piston deflection for a given engine speed, leading to reduced injection volume and a slower engine speed after all. Hmmm I think I see. In fact I think it's more likely that the governor oil was originally part oil part diesel and having had a litre or so of diesel come out of the drain now, the oil/diesel mix has all gone and been replaced with pure diesel which is why the tickover has risen slowly over the months! What do you think?

 

I'll report the results of adding oil in a while.... I'm off out to look at boats for sale tomorrow!

 

In the meantime I've made some progress on the petrol running problem. Or rather I haven't. I'll resurrect that thread with an update soon :-)

 

Mike

 

Mike,

 

I don't quite understand - you're looking in the right place. Can't you see the bits underneath the governor casing eg "governor driving shaft", "governor driven shaft" etc? All those bits in that area of the drawing are the bits from inside the casing. Don't forget it's just an illustrated parts list rather than a proper general arrangement drawing - but its the best we have sadly!

 

I've never taken a governor apart but I don't think the piston covers or uncovers the port as it moves - perhaps I shouldnt have used the word "port". It's surely just an orifice out of the cylinder similar to the other one where the fluid comes in from the gear pump. Its effective size is just controlled by the speed lever and therefore the pressure deflecting the piston against the spring force is dependent on the rate of fluid coming in caused by the pump speed less the rate of fluid leaving via the variable size hole caused by the position of the speed lever. Again just my surmise of how it works!

 

As to what the rack does in the injector pump - I would definitely get howls of protest if I tried one of my little explanations of that. Have a look at Tony Brooks site as I believe he has some good sketches and explanations on there. Basically the rack turns the outer barrels of the injector pump elements and a clever system of spiral cuts change the volume of fuel injected each time the pump plunger is raised by the cam.

 

I don't think changing the spring tension is a bad thing - certainly on a variety of engines I've played with using mechanical governors, the speed setting is indeed adjusted by altering the fixed end of the spring, usually by some sort of screwed rod anchoring it. I would just make sure you have eliminated any other causes before you do!

 

I like your theory about the oil needing to be a little more viscous than pure diesel - it ties in with Tim Leech's suggestion that your governor could be a bit worn perhaps.

 

Richard

[RLWP]

 

Mike, how about getting this thread relocated to the new Kelvin section of the forum?

 

Richard

[tom_c]

have you recently filled up with diesel? if so does a modern low sulphur diesel have a lower viscosity than the older fuels?

[BEngo]

Richard,

 

Thanks for the detailed explanation. Much appreciated.

 

Now for the inevitable questions... ;-)

 

I can't see any parts breakdown of the governor proper on Mike Skyner's site. Only the peripheral components. Maybe I'm looking in the wrong place. I'm looking at this page http://www.sky-net.org.uk/kelvin/diesel/k_range/k_parts_list/index.html in the section headed "Governor Group". Is that where you meant? Or is there a proper breakdown showing the governor components somewhere else on the site I haven't found yet?

 

I imagine the "exhaust port" in the cylinder you mention is tapered in shape and partly obscured by the piston itself in such a way that the further the piston moves the bigger the 'visible' port area becomes, moderating the increase in piston pressure against the spring as engine speed and piston travel increases. Otherwise once a certain oil pressure is reached surely the piston would be pushed right out of the cylinder, wouldn't it? (Or maybe not as the spring resistance also increases as deflection rises.)

 

 

Mike

 

 

I have taken a governor apart (both the CI and the Gunmetal ones.) The Gunmetal one is more complicated..... The CI one simply involves removing everything obvious from the outside and then undoing the row of long bolts round the edge. The plates either side will then come off- you may need to lever them off witha screwdriver, but if you look carefully there are places provided so you can do this without damaging the mating faces. There are no surprises like springs, tiny ball bearings or the like inside. Re-assembly is the reverse of dismantling. I seal the faces with hylomar (there is no gasket). Do not overtighten the glands.

 

If you take it apart it will (with the aid of Richard's excellent explanation) be obvious how it works. If you don't dismantle it then the way the speed signal is controlled is that the speed lever rotates a rod with an eccentric boss on the end. The eccentric boss covers and uncovers a port behind the piston at the end where the diesel oil is pumped by the gears. More rotation means a bigger uncovering and so less pressure to oppose the governor spring.

 

If your tickover is rising and the oil levels are correct it may be that the oil is getting too hot. Check the glands on the driving shaft are not overtight.

 

The governors were set up in the factory on a J2. I was told at Kyle St that this was used for both the K and the J governors- certainly this J2 was still in the factory, complete and running, in 1991 or 2 when I went there to buy some spare J cylinder heads. There was also the only R2 ever made.

 

N

Edited May 26, 2011 by BEngo

[rjasmith]

I have taken a governor apart (both the CI and the Gunmetal ones.) The Gunmetal one is more complicated..... The CI one simply involves removing everything obvious from the outside and then undoing the row of long bolts round the edge. The plates either side will then come off- you may need to lever them off witha screwdriver, but if you look carefully there are places provided so you can do this without damaging the mating faces. There are no surprises like springs, tiny ball bearings or the like inside. Re-assembly is the reverse of dismantling. I seal the faces with hylomar (there is no gasket). Do not overtighten the glands.

 

If you take it apart it will (with the aid of Richard's excellent explanation) be obvious how it works. If you don't dismantle it then the way the speed signal is controlled is that the speed lever rotates a rod with an eccentric boss on the end. The eccentric boss covers and uncovers a port behind the piston at the end where the diesel oil is pumped by the gears. More rotation means a bigger uncovering and so less pressure to oppose the governor spring.

 

If your tickover is rising and the oil levels are correct it may be that the oil is getting too hot. Check the glands on the driving shaft are not overtight.

 

The governors were set up in the factory on a J2. I was told at Kyle St that this was used for both the K and the J governors- certainly this J2 was still in the factory, complete and running, in 1991 or 2 when I went there to buy some spare J cylinder heads. There was also the only R2 ever made.

 

N

 

 

Wow - I'm glad I got it more or less right - thanks for your confirmation. If I ever have to take mine apart (hopefully never!) I shall be much more confident!

 

Richard

[MtB]

Mike,

 

I don't quite understand - you're looking in the right place. Can't you see the bits underneath the governor casing eg "governor driving shaft", "governor driven shaft" etc? All those bits in that area of the drawing are the bits from inside the casing. Don't forget it's just an illustrated parts list rather than a proper general arrangement drawing - but its the best we have sadly!

 

I've never taken a governor apart but I don't think the piston covers or uncovers the port as it moves - perhaps I shouldnt have used the word "port". It's surely just an orifice out of the cylinder similar to the other one where the fluid comes in from the gear pump. Its effective size is just controlled by the speed lever and therefore the pressure deflecting the piston against the spring force is dependent on the rate of fluid coming in caused by the pump speed less the rate of fluid leaving via the variable size hole caused by the position of the speed lever. Again just my surmise of how it works!

 

As to what the rack does in the injector pump - I would definitely get howls of protest if I tried one of my little explanations of that. Have a look at Tony Brooks site as I believe he has some good sketches and explanations on there. Basically the rack turns the outer barrels of the injector pump elements and a clever system of spiral cuts change the volume of fuel injected each time the pump plunger is raised by the cam.

 

I don't think changing the spring tension is a bad thing - certainly on a variety of engines I've played with using mechanical governors, the speed setting is indeed adjusted by altering the fixed end of the spring, usually by some sort of screwed rod anchoring it. I would just make sure you have eliminated any other causes before you do!

 

I like your theory about the oil needing to be a little more viscous than pure diesel - it ties in with Tim Leech's suggestion that your governor could be a bit worn perhaps.

 

Richard

 

 

Richard,

 

My question about whether I was on the right page was caused by me looking for component drawings of the piston and the cylinder in particular, to see the arrangement of ports and holes. Nor did I recognise the geared shafts as oil pump components as I was confusing a gear type oil pump with a rotor type so as rotor components were missing too, I concluded there was another page with more drawings I had yet to find!

 

Anyway yes I now understand exactly how the governor works, or at least I *think* I do :-) so thanks for that.

 

So, adjustment of the tickover speed means adjusting the position of the rack in the fuel pump. As the slowest tickover setting on the throttle spindle must correspond to the adjustable throttle port being fully closed, I think this means that any further reduction in the tickover speed must be a question of fiddling with the equilibrium of the piston/spring system to adjust the exact rack position when the throttle lever is set to tickover, ie. port closed. This assumes there is a bypass port to prevent the pressure in the cylinder rising infinitely and pushing the piston right out of the cylinder or breaking something should the adjustable port connected to the throttle lever ever be closed fully. Does anyone know if there is a bypass port? Graham's comment about being able to stop the engine by removing the tickover stop on his governor suggests there isn't, but then I think he has the earlier type of governor (gunmetal type).

 

It appears to me that assuming there IS a bypass port, any further tickover reduction this can be done by changing any or all of the following: oil viscosity, the spring stop position, the spring rate (new spring reqd for this). I can't think of any other factors involved. The spring rate must be carefully matched to the governor specification so changing that would be asking for trouble. This leaves oil viscosity and spring anchor position. Spring anchor position seems easier as all I have to do is bend the hook wire.

 

 

Tom,

 

Yes I HAVE filled up with diesel recently. It was red diesel they sold me (at Better Boating on the Thames) I think, but I was in a hurry and I didn't ask the spec of the fuel they were selling. I'll call them and find out. Whatever I have now, I think I have a mixture of red diesel and white in the system now as the fuel colour now is sort of orangey yellow colour. Neither red nor white. Maybe you have hit on the exact cause of the problem :-)

 

 

Nigel,

 

I'm reasonably sure the shaft gland is not overtight but I'll check. I don't think governor gets particularly hot as I instinctively check its temperature occasionally by feeling it, without really knowing why... but now I have a reason. Thanks for the description of dismantling and reassembly. I won't do this for now as I see no advantage to be gained, but one day I'll do it out of curiosity as is seems so straightforward from what you say. Or maybe I'll go and see Richard's as he seems up for taking his to bits out of curiosity too!

 

Mike

 

P.S. Graham, I'm happy for this thread to move across to the new Kelvin subforum, if you (or any other mods) have time to do it. It seems a more natural place for it.

[rjasmith]

Richard,

 

My question about whether I was on the right page was caused by me looking for component drawings of the piston and the cylinder in particular, to see the arrangement of ports and holes. Nor did I recognise the geared shafts as oil pump components as I was confusing a gear type oil pump with a rotor type so as rotor components were missing too, I concluded there was another page with more drawings I had yet to find!

 

Anyway yes I now understand exactly how the governor works, or at least I *think* I do :-) so thanks for that.

 

So, adjustment of the tickover speed means adjusting the position of the rack in the fuel pump. As the slowest tickover setting on the throttle spindle must correspond to the adjustable throttle port being fully closed, I think this means that any further reduction in the tickover speed must be a question of fiddling with the equilibrium of the piston/spring system to adjust the exact rack position when the throttle lever is set to tickover, ie. port closed. This assumes there is a bypass port to prevent the pressure in the cylinder rising infinitely and pushing the piston right out of the cylinder or breaking something should the adjustable port connected to the throttle lever ever be closed fully. Does anyone know if there is a bypass port? Graham's comment about being able to stop the engine by removing the tickover stop on his governor suggests there isn't, but then I think he has the earlier type of governor (gunmetal type).

 

It appears to me that assuming there IS a bypass port, any further tickover reduction this can be done by changing any or all of the following: oil viscosity, the spring stop position, the spring rate (new spring reqd for this). I can't think of any other factors involved. The spring rate must be carefully matched to the governor specification so changing that would be asking for trouble. This leaves oil viscosity and spring anchor position. Spring anchor position seems easier as all I have to do is bend the hook wire.

 

 

Tom,

 

Yes I HAVE filled up with diesel recently. It was red diesel they sold me (at Better Boating on the Thames) I think, but I was in a hurry and I didn't ask the spec of the fuel they were selling. I'll call them and find out. Whatever I have now, I think I have a mixture of red diesel and white in the system now as the fuel colour now is sort of orangey yellow colour. Neither red nor white. Maybe you have hit on the exact cause of the problem :-)

 

 

Nigel,

 

I'm reasonably sure the shaft gland is not overtight but I'll check. I don't think governor gets particularly hot as I instinctively check its temperature occasionally by feeling it, without really knowing why... but now I have a reason. Thanks for the description of dismantling and reassembly. I won't do this for now as I see no advantage to be gained, but one day I'll do it out of curiosity as is seems so straightforward from what you say. Or maybe I'll go and see Richard's as he seems up for taking his to bits out of curiosity too!

 

Mike

 

P.S. Graham, I'm happy for this thread to move across to the new Kelvin subforum, if you (or any other mods) have time to do it. It seems a more natural place for it.

 

Mike,

 

Sorry - before you decide to come rushing over (!) I have no reason to want to take my governor apart I'm afraid. Even though I've had my engine now for 6 years (good grief - have I!) I've only really run it on a trolley and never in a boat yet. It was fully rebuilt by Seaward Eng in 2005. I'd love to take the governor apart one day if ever there's a real reason to but I might have to call on Andy and John up in Glasgie before that and I'm wary of diving in too much in case they wouldn't approve!

 

Of course you'd be welcome to come and say hello any time as I've said before but sadly not to see the inside of my governor just yet!!

 

I imagine there isn't a bypass port per se in the governor but I expect the eccentric control boss on the speed control rod is prevented from fully closing the normal port due to its shape or the port's shape (BEngo will know). As you say, if it was closed completely the piston/cylinder would be subjected to an enormous pressure due to hydraulic lock.

 

Have you checked that pulling the pump rack back by hand against the spring when the engine is idling (too fast) will slow it down/stop it completely - just a thought.

 

If you do alter the spring anchor length, make sure the spring can still pull the pump rack to the full fuel position when the engine is stopped (there's a stop clamped on the rack rod near the bike chain that sets this. Don't alter this stop - it's supposed to be a Deadly Sin!)

 

Richard

[BEngo]

Mike,

 

Sorry - before you decide to come rushing over (!) I have no reason to want to take my governor apart I'm afraid. Even though I've had my engine now for 6 years (good grief - have I!) I've only really run it on a trolley and never in a boat yet. It was fully rebuilt by Seaward Eng in 2005. I'd love to take the governor apart one day if ever there's a real reason to but I might have to call on Andy and John up in Glasgie before that and I'm wary of diving in too much in case they wouldn't approve!

 

Of course you'd be welcome to come and say hello any time as I've said before but sadly not to see the inside of my governor just yet!!

 

I imagine there isn't a bypass port per se in the governor but I expect the eccentric control boss on the speed control rod is prevented from fully closing the normal port due to its shape or the port's shape (BEngo will know). As you say, if it was closed completely the piston/cylinder would be subjected to an enormous pressure due to hydraulic lock.

 

Have you checked that pulling the pump rack back by hand against the spring when the engine is idling (too fast) will slow it down/stop it completely - just a thought.

 

If you do alter the spring anchor length, make sure the spring can still pull the pump rack to the full fuel position when the engine is stopped (there's a stop clamped on the rack rod near the bike chain that sets this. Don't alter this stop - it's supposed to be a Deadly Sin!)

 

Richard

 

 

The CI (horizontal piston) governor control will eventually shut the port completely if the lever is moved down with the normal stops removed. As Graham has said this causes the engine to stop, deliberately on Alnwick, because the maximum pressure builds up to push the piston aft and pull the pump rack to the stop position. Hydraulic lock does not occur because there is a passage from the rear of the piston which allows any oil that gets on the 'wrong' side to run out. This is also necessary because the piston is a reasonably slack fit in the bore. The forward part of the piston rod has even more clearance, so that if you override the governor by manually pulling or pushing forward on the pump rack and rev the engine to say half speed (in gear -and you need to pull surprisingly hard to compete with the governor) it is possible to get diesel squirting out from the front of the governor, around the piston rod.

 

 

Nigel

[koukouvagia]

I've always been a bit puzzled to know exactly how the governor works and thanks to Richard and Nigel I've now got a much clearer idea. I'm a bit reluctant to take mine to pieces since it's working perfectly well. I've noticed on occasions that the governor needs topping up before starting, since the level of diesel has dropped below the level of the strainer. At other times the level remains filled up as far as the overflow pipe. Where does the drained diesel go to? And why does it disappear only sometimes? Is it something to do with the relative position of the piston and the relief passage? There's no leak at the gland.

 

Just curious.

Edited May 28, 2011 by koukouvagia

[BEngo]

I've always been a bit puzzled to know exactly how the governor works and thanks to Richard and Nigel I've now got a much clearer idea. I'm a bit reluctant to take mine to pieces since it's working perfectly well. I've noticed on occasions that the governor needs topping up before starting, since the level of diesel has dropped below the level of the strainer. At other times the level remains filled up as far as the overflow pipe. Where does the drained diesel go to? And why does it disappear only sometimes? Is it something to do with the relative position of the piston and the relief passage? There's no leak at the gland.

 

Just curious.

 

 

I think you must have a gunmetal governor? They have some extra bits and vertical pistons. I have had one apart to clean it as part of a rebuild and the basic principle is similar to the CI ones. There is no obvious reason for them to use diesel if there is no leak. It is possible, on either type, for the oil to get frothy and then overflow from the drain. This can occur when working hard and the engine/governor is hot.

 

The drain from the governor traditionally goes into an empty Teacher's bottle. These are fragile and it is important to have a good stock of spare replacements, preferably full as the glass is reputed to keep better like that.

 

 

If the level in the governor is not too low you can simply run the engine with an injector drain open until the level is OK.

 

N

[Timleech]

Here's a scan of the parts list drawing for the early T governor, it employs the same principle and the drawing might give more clues as to how it goes together than does the K parts list.

Don't get confused by the position of item 23 in the drawing, this is the control spindle and goes in the hole in the main block and through the gland.

A 'close control' bought-in Woodward governor was an extra cost option, and AFAIK became standard fitment on later engines (certainly was on the TA).

 

http://i559.photobucket.com/albums/ss38/Timleech_2009/mersey2010/Kelvin/KelvinTgovernor-1.gif

 

Tim

[rjasmith]

 

The drain from the governor traditionally goes into an empty Teacher's bottle. These are fragile and it is important to have a good stock of spare replacements, preferably full as the glass is reputed to keep better like that.

 

(snip 1)

 

Absolutely! But on a slightly more serious note does anyone who adheres to this splendid tradition have experience of a BSS inspection verdict on it? The BSS guide just about copes with a "metal catch pot" on vintage engines. I suppose all you do is temporarily replace the Teachers bottle with an approved container at the appropriate moment.

 

Or do you contribute one of the spare bottles you keep, that has yet to have been made ready for its new role, to your BSS inspector in the hope that it will cause his verdict to be more favourable?

 

 

If the level in the governor is not too low you can simply run the engine with an injector drain open until the level is OK.

 

N

 

(snip 2)

 

Although of course in Mike's case this won't be quite so successful!

 

Richard

[MtB]

Although of course in Mike's case this won't be quite so successful!

 

Richard

 

 

Excuse me but I can run with an injector drain open perfectly easily. It's just my engine that can't... :-DDD

 

Ok an update:

 

Been away for the weekend on the boat, and having at last fixed the rev counter I have established that tickover from cold up to about 120 degrees F is a little over 160rpm. Above 120F it rises progressively to about 220 rpm with the engine at 155F according to the roof gauge. (155F on the roof gauge corresponds to 145F on the engine room gauge and I dunno which, if either, is correct - both gauges are brand new!) This is after draining the governor and re-filling with new diesel.

 

Fiddling with the rack spring hook reveals I'm not the first to try and the hook length has been carefully adjusted so the spring coils 'just' do not quite fully close at full throttle, so adjusting the spring length further is not an option.

 

I'm not prepared to fiddle with the spring temper or do anything to adjust the spring rate so that just leaves adding oil to the governor fluid. I added about a tablespoon of engine oil from my oilcan to the chamber with the engine at 145F and ticking over at 200rpm, and as I added it the tickover speed fell to 165rpm. Result! Sort of.

 

When cold the engine will not tick over unless I open the throttle slightly. No big problem. After a day's running today though I notice tickover at 150F (on the roof gauge) has crept back up to 180rpm. Doh!

 

So almost, but not quite, back to square one....

 

Mike