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JP3 running speed


Capella247

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having owned a boat with a jp3 for less than a year, in what has been a busy year,  I'm still getting use to it.   I find that it takes a while for me find the a point where it will settle at a relatively steady but constant rpm.   It either wants to run really fast or gradually slow and stall.     This could be due to the alternator running off the flywheel and the state of the battery charge.   It does run away following an initial charge and then after adjusting will settle again.   When I'm chugging a long it can be easier but it can randomly speed away or indeed slowdown and stall.   Is this part of the fun of a JP3 or does it point to it needing some fettling?   if some servicing is needed can anyone recommend someone?  The boats mooring is just outside Bath.   It's an industrial unit set to 1000 rpm according to the plate.   I'm not sure if that makes a difference?

Any advice gratefully received.

 

Tom

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If it is  not maintaining the speed you set there is something wrong with the governing.  Increased load should see it slow a little ( with a bit more bark to the exhaust) and reducing the load should cause it to speed up a little ( and have a softer exhaust note) but generally it should not run away up or down in speed.

 

Check that the injection pump rack is not sticking or stiff first.  Then look at the setup of the governor.  A fixed speed industrial engine has a different set of springs to those in a variable speed engine and there is usually only provision for minor speed vatiation.  I guess yours has been converted from fixed to variable speed and it may or may not have been done using factory parts.

N

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6 minutes ago, BEngo said:

If it is  not maintaining the speed you set there is something wrong with the governing.  Increased load should see it slow a little ( with a bit more bark to the exhaust) and reducing the load should cause it to speed up a little ( and have a softer exhaust note) but generally it should not run away up or down in speed.

 

Check that the injection pump rack is not sticking or stiff first.  Then look at the setup of the governor.  A fixed speed industrial engine has a different set of springs to those in a variable speed engine and there is usually only provision for minor speed vatiation.  I guess yours has been converted from fixed to variable speed and it may or may not have been done using factory parts.

N

There's a chance the pump is worn too. The chances of a fixed speed industrial JP3 getting a 'proper' set of Lister speed controls are pretty slim

 

Richard

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My 74 year old industrial JP3 had governing issues at low revs until I had the injectors serviced and the fuel pump calibrated. Ticks over at a steady 290 rpm and a decent cruising speed is achieved at 500 rpm with a 1:1 gearbox.

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8 hours ago, RAP said:

My 74 year old industrial JP3 had governing issues at low revs until I had the injectors serviced and the fuel pump calibrated. Ticks over at a steady 290 rpm and a decent cruising speed is achieved at 500 rpm with a 1:1 gearbox.

Thanks for responding, where did you have the pump calibrated?    Tom

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When I first had mine I had a small amount of trouble at low rpm which improved when I cleaned and oiled the governor rod, where it entered the engine block. A quantity of dirt had built up and the movement wasn't as smooth as it should have been. 

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5 minutes ago, BWM said:

When I first had mine I had a small amount of trouble at low rpm which improved when I cleaned and oiled the governor rod, where it entered the engine block. A quantity of dirt had built up and the movement wasn't as smooth as it should have been. 

I’ll shall give this ago sounds like something to that’s within my skill set ! 

6 minutes ago, RLWP said:

We can get your pump and injectors serviced for you

 

Richard

Thanks Richard,  I’ll be in touch 

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Before you start spending money on getting your fuel gear serviced (and I don't think it is that for a moment) examine the speeder spring at the end of the bell crank that the injector pump is connected to. The use of the correct spring at the right tension is paramount in getting a JP to run smoothly. If you have the wrong spring, or the throttle linkage has been connected without a spring, the engine will hunt, stall and generally act up. We often see JPs with the wrong spring or no spring. It is important to have the right spring, any old spring won't do. Marine Power Services have them on the shelf and you can get them from the online shop. 

Fit a new one , lubricate all the pump linkage, making sure that the governor rod that acts on the bell crank moves freely ,and not forgetting to fill the oil reservoir in the pump. Ensure that you have a cold start cam on the other end of your injector pump. (This allows excess fuel for cold starting and prevents over fuelling during normal running). Adjust your throttle linkage to put a little tension on the spring. In operation the throttle pulls against the spring to operate the pump rack but is easily overcome by the governor rod acting against it. While running the governor and throttle spring will settle to an equilibrium and your engine will run steadily unless you try to over speed it. Tick over and fast idle is usually set on the on engine throttle on JP (M) engines. If you have an industrial engine you are unlikely to have it and should make provision for adjustment without compromising the operation of the throttle spring. 

 

Properly set up JPs are a robust and smooth running engine. Take a look at the videos on the MPS website to see how smooth they should be ?

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Which leaves you in much the same position as when you asked in the first place - you really need someone to come and visit your boat. Steamraiser is a lot closer to you than I am

 

I'd be interested to know who built your boat

 

Richard

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52 minutes ago, RLWP said:

Which leaves you in much the same position as when you asked in the first place - you really need someone to come and visit your boat. Steamraiser is a lot closer to you than I am

 

I'd be interested to know who built your boat

 

Richard

Hi Richard,  Its a Paul Barber (2002).  Speaking to Paul earlier in the year about the gear box,  he said he hadn't installed a JP3 with a Borg Warner gear box so not sure if that has since been changed or whether it was installed by someone else.  According Crowther's and the job card for the propeller was for Paul,  but not for that engine / gear box combination.  So who knows !

 

4 hours ago, steamraiser2 said:

Before you start spending money on getting your fuel gear serviced (and I don't think it is that for a moment) examine the speeder spring at the end of the bell crank that the injector pump is connected to. The use of the correct spring at the right tension is paramount in getting a JP to run smoothly. If you have the wrong spring, or the throttle linkage has been connected without a spring, the engine will hunt, stall and generally act up. We often see JPs with the wrong spring or no spring. It is important to have the right spring, any old spring won't do. Marine Power Services have them on the shelf and you can get them from the online shop. 

Fit a new one , lubricate all the pump linkage, making sure that the governor rod that acts on the bell crank moves freely ,and not forgetting to fill the oil reservoir in the pump. Ensure that you have a cold start cam on the other end of your injector pump. (This allows excess fuel for cold starting and prevents over fuelling during normal running). Adjust your throttle linkage to put a little tension on the spring. In operation the throttle pulls against the spring to operate the pump rack but is easily overcome by the governor rod acting against it. While running the governor and throttle spring will settle to an equilibrium and your engine will run steadily unless you try to over speed it. Tick over and fast idle is usually set on the on engine throttle on JP (M) engines. If you have an industrial engine you are unlikely to have it and should make provision for adjustment without compromising the operation of the throttle spring. 

 

Properly set up JPs are a robust and smooth running engine. Take a look at the videos on the MPS website to see how smooth they should be ?

Thanks Steamraiser - i'll order a spring and do a clean up and see if that helps.  It doesn't have an override cam it has a round stopper on the end,  so maybe one of those will help too - I'm about to look on the MPS website... 

 

Regards

Tom 

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6 minutes ago, Capella247 said:

Hi Richard,  Its a Paul Barber (2002).  Speaking to Paul earlier in the year about the gear box,  he said he hadn't installed a JP3 with a Borg Warner gear box so not sure if that has since been changed or whether it was installed by someone else.  According Crowther's and the job card for the propeller was for Paul,  but not for that engine / gear box combination.  So who knows !

 

Thanks for that, not the builder I was expecting - which is a good thing

 

Richard

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I echo steamraiser2’s advice,  had fitted their spring and cam, ensured free and lubricated movement of the governing gear, but I state again, that it wasn’t until I had the injectors serviced and the pump calibrated I achieved a smooth and beautifully running JP3. I should also state that I fully overhauled the engine prior to that which included crank regrind, remetalled shells, new liners, piston rings etc. 

I compare the servicing of the injectors and fuel pump to that of any old vehicle engine that uses spark plugs and contacts, replace with new and your engine is more likely to thank you for it. 

 

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1 hour ago, RAP said:

I echo steamraiser2’s advice,  had fitted their spring and cam, ensured free and lubricated movement of the governing gear, but I state again, that it wasn’t until I had the injectors serviced and the pump calibrated I achieved a smooth and beautifully running JP3. I should also state that I fully overhauled the engine prior to that which included crank regrind, remetalled shells, new liners, piston rings etc. 

I compare the servicing of the injectors and fuel pump to that of any old vehicle engine that uses spark plugs and contacts, replace with new and your engine is more likely to thank you for it. 

 

The injector pump on a JP is a primitive beast at best. Problems with it,and the injectors, usually display in a different manner than a hunting engine. A defect in the delivery of fuel such as a leaking element would cause a constant fault not a transitional one. This is why I would check and service the pump linkage and speeder spring first. The other thing,which I forgot to mention earlier, is to check the condition of the little ball bearings in the bell crank itself. They often sieze or break up which affects the operation of the linkage. These are all the cheap options ?

If careful attention to these areas doesn't cure it the road to serious expenditure awaits.  Getting  fuel pumps and injectors reconditioned is an expensive business especially as it's a dying skill set these days. I strongly advise ensuring that everything else is correct first before dashing to the pump shop.

 

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Again, steamraiser2 offers good and solid advice. The servicing of my injectors and pump was the last item on the long road to getting my old and worn out engine into a satisfactory running condition. What I lacked along this journey was others to compare my experiences with. I queried things on here, spoke to experts in the industry but it would have been great to have simply shared my trials and tribulations with other JP owners. To this day I still don’t know any other JP owners. 

It has been an expensive process but please do make some basic and cost free checks before shelling out. For me, the decisions were easy once I had made these basic checks coupled with the knowledge that my engine was quite knackered.

 

 

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I got my injectors and fuel pump serviced in Leeds. There’s another in Shipley, Bradford, but there will be others closer to you. It’s just a case of seeking them out, and finding those who can still service with the skills to cope with the old stuff.

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Diagnosing a pump isn't usually too hard on an old JP. If the oil level in the pump is going up - it needs a rebuild

 

That generally cures a nasty rattle and prevents the cam getting worn out

 

Richard

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9 hours ago, RAP said:

I got my injectors and fuel pump serviced in Leeds. There’s another in Shipley, Bradford, but there will be others closer to you. It’s just a case of seeking them out, and finding those who can still service with the skills to cope with the old stuff.

I note that you say "serviced". Sadly that is where things are not as they once were. In my experience "serviced" and "re-conditioned" are poles apart. "Serviced" can often mean a clean and testing on a pop tester , with adjustment as required for the injector and a run on a Hartridge machine for the pump. A check and adjustment of the phasing and general calibration and that is it. £350 please, thank you very much.

To overhaul the pump is a straight forward process, elements at an average of £30 a go, typically a pump cam shaft is about £100 (if you can find one) delivery valves are about £15 each. Add to that a set of bearings and seals/gaskets and it is easy to see that a "re-conditioned" pump should set you back about £500.

 

With many of the old school fuel guys retiring, and the younger ones not having a clue unless it plugs into a laptop ,old fashioned fuel injection specialists are an endangered breed. Thankfully we do our own having been dismayed at the poor quality and overpricing that is out there. Don't get me wrong there are still some experts out there but they are thin on the ground. As most of you know we are based in the West Country. There is a good guy in Cornwall, we do our own in Dorset and there is a chap in Berkshire. Other than that we don't know of anyone left that can provide a service that is up to a good standard.

 

So as I keep saying, just be sure to check everything else before blaming the fuel pump and injectors. Don't go there unless you have to.

 

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10 hours ago, RAP said:

Again, steamraiser2 offers good and solid advice. The servicing of my injectors and pump was the last item on the long road to getting my old and worn out engine into a satisfactory running condition. What I lacked along this journey was others to compare my experiences with. I queried things on here, spoke to experts in the industry but it would have been great to have simply shared my trials and tribulations with other JP owners. To this day I still don’t know any other JP owners. 

It has been an expensive process but please do make some basic and cost free checks before shelling out. For me, the decisions were easy once I had made these basic checks coupled with the knowledge that my engine was quite knackered.

 

 

Thanks RAP, and everyone for your advice.  I have ordered the spring and a pawl from MPS's website and will try this when it arrives, along with lubricating and cleaning advice.  

And then the bearings, and then if that's not helped look to get the pump and injectors checked. 

I went through the manual last night so have a better idea of the terminology and the location of the parts described above.  

I'll update the thread with progress once the spring and pawl arrive.

 

 

 

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The spring arrived yesterday and has made a huge difference.   Whilst it still searches a little bit it soon settles down and doesn't speed up or stall.  So that's a great result!  in comparison to the older spring the lever is moving a lot more.  I did also wonder about the other two springs - there is one on one on the pump rack that connects the rack to the  lever  and the one that fits around the governor rod and pushes against the bell house.   The one on the pump rack (isn't in the manual ) but it looks original just not sure about the one around the governor rod - presumably these could have an affect on the running speed?

 

I still need to do a bit of adjustment as the spring is a lot shorter may add a small key ring loop to allow it run a bit slower - is that logical?

 

Tom

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1 hour ago, Capella247 said:

The spring arrived yesterday and has made a huge difference.   Whilst it still searches a little bit it soon settles down and doesn't speed up or stall.  So that's a great result!  in comparison to the older spring the lever is moving a lot more.  I did also wonder about the other two springs - there is one on one on the pump rack that connects the rack to the  lever  and the one that fits around the governor rod and pushes against the bell house.   The one on the pump rack (isn't in the manual ) but it looks original just not sure about the one around the governor rod - presumably these could have an affect on the running speed?

 

I still need to do a bit of adjustment as the spring is a lot shorter may add a small key ring loop to allow it run a bit slower - is that logical?

 

Tom

I have a similar ring on one end of my spring and it works perfectly. 

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There is no need for a spring fitted to the pump rack. I suggest you remove it.The rack and connected linkage should be very free to move. If it feels notchy check the bearings in the bell crank. They tend to get rusty over the years. They are very cheap to buy. The spring on the end of the governor rod that acts against the bell crank is meant to be there. Check that there is a gap of around 3mm between the end of the rod and the bell crank stop bolt. The little gap and spring enable a little movement before the rod pushes the bell crank and closes the pump. This also helps the level running so is worth checking out. 

 

Would I be right in presuming that the speeder spring is connected to a throttle rod? If it is you should really get a longer rod rather than put a key ring into it. Lister designed the variable speed JPs to have a rodded throttle as it pushes as well as pulls. It will not push as intended with a key ring in it. Over the years I have seen a lot of JPs hooked up to Morse controls. The ones with the cables connected to a Lister throttle unit work satisfactorily the ones directly onto the speeder spring or, worse still,onto the bell crank act against the intended operation of the speed control arrangement. Avoid this arrangement if at all possible. Any installation that prevents the throttle self regulating and works against the governor could lead to over speeding and may end up causing crank failure to which JPs are prone.

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2 hours ago, steamraiser2 said:

 Over the years I have seen a lot of JPs hooked up to Morse controls. The ones with the cables connected to a Lister throttle unit work satisfactorily the ones directly onto the speeder spring or, worse still,onto the bell crank act against the intended operation of the speed control arrangement. Avoid this arrangement if at all possible. Any installation that prevents the throttle self regulating and works against the governor could lead to over speeding and may end up causing crank failure to which JPs are prone.

I'm not sure I see the logic in this as the spring works in tension only (until coil bound then I guess you could push on it), but I'll be trying out this very thing (morse control onto the speeder spring) on the JK4 later today in the workshop so will report back. :)

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