SR2 smoking

[bizzard]

Firstly Claudia is a 1977 unknown builder 33 foot cruiser stern narrow boat that has certainly seen better days. The stop is a cable going to a cam on the port side of the engine. The video shows the engine being started for the first time today in a temperature of 3 degrees.

An SR2 is plenty of power for a n/b of that length. Where that cam is under the hot air outlet trunking would be the governor adjustment engine stop unit plate with the adjusting bolt holding it.The throttle cable ends up close by it too.

I'd say your engine was almost certainly an ex industrial hand-start one,hence those cold start oil plungers,as most marine n/b SR engines are electric start only and so would not really require them.They are also direct- injection engines not requiring any electric combustion chamber heater glow plugs,unlike an indirect- injection diesel engine.

But we're still not certain which engine you have SR,SL or LR.

As Tim Leech mentioned why not PM Chris B,as i think he has access to most of the Lister blurb.And might be able to identify it for you.

[PhilR]

An SR2 is plenty of power for a n/b of that length. Where that cam is under the hot air outlet trunking would be the governor adjustment engine stop unit plate with the adjusting bolt holding it.The throttle cable ends up close by it too.

I'd say your engine was almost certainly an ex industrial hand-start one,hence those cold start oil plungers,as most marine n/b SR engines are electric start only and so would not really require them.They are also direct- injection engines not requiring any electric combustion chamber heater glow plugs,unlike an indirect- injection diesel engine.

But we're still not certain which engine you have SR,SL or LR.

As Tim Leech mentioned why not PM Chris B,as i think he has access to most of the Lister blurb.And might be able to identify it for you.

 

I have not seen a marine SR that is electric start only, apart from a few installations where it is impossible to fit and swing a starting handle. But I might have misunderstood your post?

 

Phil

[bizzard]

I have not seen a marine SR that is electric start only, apart from a few installations where it is impossible to fit and swing a starting handle. But I might have misunderstood your post?

 

Phil

High Phil. Strange.I think most of the overhead type were taken off as most old ex hire boats would not bother with them especially cruiser stern boats as in a lot of cases would be too high for deck board clearance,and most of these old SR's ect engines i think were fitted to hire boats. Privately owned boat owners would probably have insisted on them as back up though.

There are two types of starting handle arrangements.The overhead type turning a chain and ratchet sprocket on the cam shaft,which i find is rare on a N/B but more popular in sea boats and small open fishing boats ect. And provision on the protruding camshaft stub for a handle,but is usually too low down or too obstructed to try and use.

I've seen the overhead type on the 3 cyl Lister engines SR3,SL3,ST3 and of course their water cooled variants quite frequently though in N/B's,usually as back up to an electric starter. I often see evidence of an engine having had the overhead type but long been taken off,unless its maintained,chain and sprockets oiled ect most i think became knackered and removed.We have three boats here with these engines none of which have the overhead gear and no evidence of having had,though funnily enough my own ST2 marine does have evidence of one,the front upright casting which once contained the bearing bush for the handles shaft is all that's left.

Edited December 15, 2011 by bizzard

[by'eck]

But you're still requesting a further increase in revs and the only way you get a diesel to accelerate is to inject more fuel (as they run in excess of freely available air) and so in a non-steady-state (ie acceleration under load) you will always be injecting some excess fuel or it won't accelerate further. Steady state conditions I agree with you completely, but I can't see how you're going to get the engine to accelerate without running some excess of fuel. Even hi-tech common rail engines in cars smoke more during acceleration and they have very finely controlled mixture delivery.

Roger

 

I think you & Tim are both right. The revs must increase first before more fuel is injected though. The modern governor is a very subtle device, & will only try to accelerate engine with increased throttle position.

 

As an example, I caught a piece of fishing net on my prop. The effect was to reduce revs to just a little over idle. The morse control had no effect other than to increase revs about 100 rpm over idle in forward. The engine showed no signs of stress or excess smoke of any kind. It was almost as though the throttle bowden cable had broken. Limped back to port to find said fishing net hooked around prop like a hair net. Removed it & everything back to normal.

[Albion]

I think you & Tim are both right. The revs must increase first before more fuel is injected though. The modern governor is a very subtle device, & will only try to accelerate engine with increased throttle position.

 

As an example, I caught a piece of fishing net on my prop. The effect was to reduce revs to just a little over idle. The morse control had no effect other than to increase revs about 100 rpm over idle in forward. The engine showed no signs of stress or excess smoke of any kind. It was almost as though the throttle bowden cable had broken. Limped back to port to find said fishing net hooked around prop like a hair net. Removed it & everything back to normal.

 

Let me quote you please from the Bosch Automotive Handbook 4th edition, Engine Management (Diesel Engines), Page 506, first section on Fuel Metering (book obtained when I was a qualified Bosch Systems Technician during my garage ownership):-

 

The fuel quantity alone is used for diesel-engine load and speed control; its intake air is not throttled. Because an unloaded diesel engine can respond to excessive injection flow by continuing to gain speed to the point of self-demolition a governing device is essential.

 

Further on there is a diagram of how a variable speed governor works and it (in words) is as follows:-

 

When a faster engine speed is requested, the fuel control lever on the pump (a throttle control lever operated by you, by your control cable, back to your speed lever/Morse control at the steering position) opens the rack causing more fuel to be injected. When the engine has accelerated to meet the set point rpm that you have chosen the governor weights are flung out to the point where they just over-ride the requested input and the set point rpm is maintained. If the load on the engine is increased, while the fuel control lever remains in the same position, the revs fall and the governor weights swing in which causes more fuel to be injected in an attempt to increase the rpm back to the set position. If that chosen rpm can be obtained then the governor again controls the rpm around the set position. If, however, the revs cannot be achieved due to a massive over-load condition then the governor will still continue to request more fuel while it attempts to regain the set rpm (and the engine will be running an over-fuel condition and black smoking .... my words in these brackets)

 

There is no way a diesel engine can increase its rpm without more fuel being injected (unless the load is driving the engine of course) and I refer you back to the quote from the Bosch Handbook for confirmation.

 

The system that I have described above is, by the way, the very simplest mechanical system. There are many refinements on the basic system for idle stability control and all sorts of other things to add refinement and to reduce emissions. This has culminated in today's Common Rail systems with very sophisticated multi-pulse injection events (of up to about 5 per injection event) but this is far from the simple mechanical system on most basic, older, engines in boats.

Roger

[claudia]

So what you are saying Roger is I must be over proped.

 

Also replying to your earlier post no way did I wish to imply that Crowthers had misled me in anyway I fully understand they can and indeed anyone else can only go on data given.

[Chris Pink]

So what you are saying Roger is I must be over proped.

 

Also replying to your earlier post no way did I wish to imply that Crowthers had misled me in anyway I fully understand they can and indeed anyone else can only go on data given.

 

so examining this position, some more information please.

 

The black smoke you mention in Post #1;

 

with the engine in gear is this at all revs? or high revs? at idle? is there a point where the engine speed does not increase but the amount of black smoke does?

 

with the engine out of gear, will it rev (a lot) higher than in your video?

[Albion]

So what you are saying Roger is I must be over proped.

 

Also replying to your earlier post no way did I wish to imply that Crowthers had misled me in anyway I fully understand they can and indeed anyone else can only go on data given.

 

No, I didn't get the impression that you were saying that Crowthers had misled you. These things happen and we must get to the bottom of the problem by sound, logical, reasoned diagnosis, to be confirmed at a later date when you've solved the problem

 

Obviously it is difficult to diagnose over the web but we have the following info:-

1. The engine revs normally when not in gear.

2. The video shows that nothing seems significantly wrong with either cylinder and because the response from both cylinders was so similar when you de-compressed each it suggests that the fuelling is balanced too. I would also have liked by the way, on your video, to have heard the engine note when put in gear and revved, and also a shot of the black smoke under load.

3. You can rotate the prop shaft easily.

 

So, what are we left with?

1. A partially seized gearbox - unlikely but still remotely possible.

2. Insufficient fuel delivery to the engine to sustain full load output - possible, but unlikely due to the black smoking which suggests over-fuelling, not lack of fuelling.

2. The load on the engine is not matched to the output......why could this be?.......possible over-propping for some reason maybe. This could be for various reasons; incorrect info supplied to prop suppliers; engine smaller power output than you think it is; prop is not actually the size you think it is; prop isn't correctly stamped even though you have seen the stamped size physically if the boat was out of the water etc etc.

 

On balance I suspect over-propping but I've not been party to what you have done, what you have seen, whether the boat has been out of the water while all this has been happening etc. Two questions/thoughts though:-

1. Are you absolutely sure that the prop you have on the boat is the prop of the size specified by Crowther's calculations?

2. You must get the engine type and hence its max power established.

 

Hope this helps in some small way, but we must drill down to the root cause of the problem otherwise we will be going round in circles basing diagnosis on assumed information. One thing that I have learnt in my career in the motor trade is never to assume anything and that, also, man-made faults are often the hardest to diagnose.

Roger

[Timleech]

 

 

When a faster engine speed is requested, the fuel control lever on the pump (a throttle control lever operated by you, by your control cable, back to your speed lever/Morse control at the steering position) opens the rack causing more fuel to be injected. When the engine has accelerated to meet the set point rpm that you have chosen the governor weights are flung out to the point where they just over-ride the requested input and the set point rpm is maintained. If the load on the engine is increased, while the fuel control lever remains in the same position, the revs fall and the governor weights swing in which causes more fuel to be injected in an attempt to increase the rpm back to the set position. If that chosen rpm can be obtained then the governor again controls the rpm around the set position. If, however, the revs cannot be achieved due to a massive over-load condition then the governor will still continue to request more fuel while it attempts to regain the set rpm (and the engine will be running an over-fuel condition and black smoking .... my words in these brackets)

 

There is no way a diesel engine can increase its rpm without more fuel being injected (unless the load is driving the engine of course) and I refer you back to the quote from the Bosch Handbook for confirmation.

 

The system that I have described above is, by the way, the very simplest mechanical system. There are many refinements on the basic system for idle stability control and all sorts of other things to add refinement and to reduce emissions. This has culminated in today's Common Rail systems with very sophisticated multi-pulse injection events (of up to about 5 per injection event) but this is far from the simple mechanical system on most basic, older, engines in boats.

Roger

 

The governor or pump will include a maximum fuel stop, if this is correct set then it will prevent overloading and black smoke, the engine will simply fail to accelerate. Depending on the engine, some may be set up to allow a hint of smoke.

Modern diesel cars are more high tech, with computerised control, and they do tend to give a puff of smoke when you put your foot down, some makes are much worse than others, I suspect this is more to do with turbo lag and a compromise to get good acceleration figures than anything else.

 

As I tried to say before, in the case of a boat propulsion engine it is not usually working at anywhere near to maximum power/torque capability until it gets near to full speed so 'acceleration' is not a problem.

 

Incidentally I have just collected a set of three injectors for an SR3, it was running OK but a bit smoky, all three were badly carboned up internally and needed major work.

 

Tim

Edited December 15, 2011 by Timleech

[Albion]

The governor or pump will include a maximum fuel stop, if this is correct set then it will prevent overloading and black smoke, the engine will simply fail to accelerate. Depending on the engine, some may be set up to allow a hint of smoke.

snipped

 

OK, so you have a fuel lever on the max speed setting but the engine is unable to reach max speed due to load for example.

1. Is the governor still trying to attain max speed?

2. If isn't, why not?

3. If it is still trying to increase the speed to the max set point, is it doing so by increasing the fuel supplied? If not fuel (in your opinion) then what else is it doing to increase the speed?

4. If extra fuel is being supplied to accelerate the engine to the set speed, is that quantity more than actually required to maintain the speed that it can achieve?

Roger

[Timleech]

OK, so you have a fuel lever on the max speed setting but the engine is unable to reach max speed due to load for example.

1. Is the governor still trying to attain max speed?

2. If isn't, why not?

3. If it is still trying to increase the speed to the max set point, is it doing so by increasing the fuel supplied? If not fuel (in your opinion) then what else is it doing to increase the speed?

4. If extra fuel is being supplied to accelerate the engine to the set speed, is that quantity more than actually required to maintain the speed that it can achieve?

Roger

 

1. yes

 

2. see 1.

 

3. No, it can't, the engine is already overloaded. Nothing.

 

4. Not for a marine propulsion engine. Or, strictly, it doesn't need to be more.

 

Tim

[bizzard]

My cousin who had an old Rugby boats ex hire boat with an SR2 years ago who was traveling the system and on his way back up the Stort rang me at work To tell me he'd suddenly lost power and could only run at just over idle speed when in gear,but would rev in neutral.I told him what checks to do and ring me back,no joy,so i went out to him after work at Sawbridgeworth,after many checks,prop checked,air in fuel system,ect,ect,now getting dark.The last resort,over ride the governor,which i did by turning anti-clockwise the ''control lever adjusting plate'',as explained how to do to Ian earlier,a 20 sec job,and it did the trick,normal power restored.

To get to these governors is quite a nasty job with the engine in a boat.

My cousin was perfectly happy as it was so it was left alone.What had happened to the governor mechanism i'm not sure,maybe the transfer rod had bent or internal adjustment shifted i don't no,as is all buried behind the timing gear case. Any how that boat is still running like it,just had to be careful not to over rev in neutral and that was it.

I think its worth a try on Ian's.

We also need to know exactly which engine it is as the power differences are quite substantial.

[Tony Brooks]

The governor or pump will include a maximum fuel stop, if this is correct set then it will prevent overloading and black smoke, the engine will simply fail to accelerate. Depending on the engine, some may be set up to allow a hint of smoke.

Modern diesel cars are more high tech, with computerised control, and they do tend to give a puff of smoke when you put your foot down, some makes are much worse than others, I suspect this is more to do with turbo lag and a compromise to get good acceleration figures than anything else.

 

As I tried to say before, in the case of a boat propulsion engine it is not usually working at anywhere near to maximum power/torque capability until it gets near to full speed so 'acceleration' is not a problem.

 

Incidentally I have just collected a set of three injectors for an SR3, it was running OK but a bit smoky, all three were badly carboned up internally and needed major work.

 

Tim

 

 

I think there is every chance that in the above situation it will smoke.

 

I thought it was accepted that indirect injected engines were developed because lack of swirl in a direct injected engine's combustion space at low speed caused combustion problems. This is more pronounced on small cylinder volumes, hence the 1,2, & 3 cylinder engines.

 

If something is artificially holding the revs as low as Claudia seems to suggest then the air velocity in the combustion area would be low so the burning fuel droplets sort of run out of oxygen and go out eventually - hence the production of CO and eventually C.

 

I agree about injectors that are not atomising the fuel properly (from any cause - carbon or not) because in this case the fuel droplets may be "too big" to burn properly in the time available.

 

All a bit theoretical for most everyday problems but it tends to explain why Listers, Bukhs and Shires can smoke a bit on idle although they are well maintained.

 

1. yes

 

2. see 1.

 

3. No, it can't, the engine is already overloaded. Nothing.

 

4. Not for a marine propulsion engine. Or, strictly, it doesn't need to be more.

 

Tim

 

3. The engine may be overloading but all that means is that the user's control has compressed the governor spring and forced the pump into a position where it is supplying more fuel than required to run at the present speed. That is overloading and the system IS supplying more fuel in an attempt to accelerate the engine - hence the black smoke.

 

4.No difference between a marine, industrial, agricultural or automotive engine (petrol or diesel come to that). If you want more speed you need more power to accelerate the engine and more power = more fuel. I fear you are wrong on this one Tim. No more fuel and there will be no extra power to accelerate the engine. The problem here appears to be that something external may be holding the speed down.

 

Edited to add:-

 

It may well be that the governer actually goes into an excess fuel position when stationary on engines that have no excess fuel control (cold start).

Edited December 15, 2011 by Tony Brooks

[Albion]

I think there is every chance that in the above situation it will smoke.

 

I thought it was accepted that indirect injected engines were developed because lack of swirl in a direct injected engine's combustion space at low speed caused combustion problems. This is more pronounced on small cylinder volumes, hence the 1,2, & 3 cylinder engines.

 

If something is artificially holding the revs as low as Claudia seems to suggest then the air velocity in the combustion area would be low so the burning fuel droplets sort of run out of oxygen and go out eventually - hence the production of CO and eventually C.

 

I agree about injectors that are not atomising the fuel properly (from any cause - carbon or not) because in this case the fuel droplets may be "too big" to burn properly in the time available.

 

All a bit theoretical for most everyday problems but it tends to explain why Listers, Bukhs and Shires can smoke a bit on idle although they are well maintained.

 

 

 

3. The engine may be overloading but all that means is that the user's control has compressed the governor spring and forced the pump into a position where it is supplying more fuel than required to run at the present speed. That is overloading and the system IS supplying more fuel in an attempt to accelerate the engine - hence the black smoke.

 

4.No difference between a marine, industrial, agricultural or automotive engine (petrol or diesel come to that). If you want more speed you need more power to accelerate the engine and more power = more fuel. I fear you are wrong on this one Tim. No more fuel and there will be no extra power to accelerate the engine. The problem here appears to be that something external may be holding the speed down.

 

Edited to add:-

 

It may well be that the governer actually goes into an excess fuel position when stationary on engines that have no excess fuel control (cold start).

 

Thank you Tony, exactly what I have been arguing.

Roger

[Timleech]

I think there is every chance that in the above situation it will smoke.

 

I thought it was accepted that indirect injected engines were developed because lack of swirl in a direct injected engine's combustion space at low speed caused combustion problems. This is more pronounced on small cylinder volumes, hence the 1,2, & 3 cylinder engines.

 

If something is artificially holding the revs as low as Claudia seems to suggest then the air velocity in the combustion area would be low so the burning fuel droplets sort of run out of oxygen and go out eventually - hence the production of CO and eventually C.

 

I agree about injectors that are not atomising the fuel properly (from any cause - carbon or not) because in this case the fuel droplets may be "too big" to burn properly in the time available.

 

All a bit theoretical for most everyday problems but it tends to explain why Listers, Bukhs and Shires can smoke a bit on idle although they are well maintained.

 

 

 

3. The engine may be overloading but all that means is that the user's control has compressed the governor spring and forced the pump into a position where it is supplying more fuel than required to run at the present speed. That is overloading and the system IS supplying more fuel in an attempt to accelerate the engine - hence the black smoke.

 

4.No difference between a marine, industrial, agricultural or automotive engine (petrol or diesel come to that). If you want more speed you need more power to accelerate the engine and more power = more fuel. I fear you are wrong on this one Tim. No more fuel and there will be no extra power to accelerate the engine. The problem here appears to be that something external may be holding the speed down.

 

Edited to add:-

 

It may well be that the governer actually goes into an excess fuel position when stationary on engines that have no excess fuel control (cold start).

 

Agreed if the engine is fully loaded well below its rated speed it might be a little bit smoky through inefficient combustion but claudia talks about 'a lot of black smoke'.

 

3. You seem a bit muddled on this one. If the pump is supplying more fuel than needed to run at the present speed, the speed will increase. We've already been told (in Albion's hypothetical case) that it won't go any faster. Agreed that if it's supplying more fuel than the engine can burn properly, it will smoke in this situation. My argument is that with a properly set up and maintained engine, that smoke should be minimal. A lot of black smoke (which is what claudia says they have) indicates to me either that something is wrong with the fuel injection, OR there's an overload AND an error in the setup (or poor maintenance). Maybe someone has already tried Biz's bodge on the governor settings

 

4. Marine propulsion provides a particular sort of load (with ordinary low speed boats, at least. Phylis' case might be different )

The load increases with rpm at a much greater rate than does the available engine output. If the engine/prop combination is running significantly below the maximum rpm it's capable of, then the engine should easily be able to increase that rpm without any fuel delivery above that needed for full power. Yes of course it will need more fuel than it has been delivering at the earlier steady state speed, there's no argument about that, it just won't need to overfuel in any way. It's only if it's already running at the speed where power and load curves intersect that excess fuel will be needed, with the attendant smoke. Again, if the engine is properly set up, that shouldn't happen anyway.

 

Tim

Edited December 15, 2011 by Timleech

[bizzard]

On the engines in question,the governor setting for maximum revs and load is a very fine one as is the setting of the set ups on other types of engine for load and revs sensing.The air cooled engines governors need to be more sensitive as these engines are only cooled by rev sensing,the higher the revs the faster the flywheel fan turns and progressively supplies more air as the revs increase, and not load sensing as in thermostatically controlled water cooled engines.

Therefore the air cooled engine can more easily overheat if overloaded

The governor arrangement on the engines in question is very delicate involving very light compression springs on and between the injector pumps rack spindles which cushion and steady these to prevent hunting and general unsteady running especially when idling.This action working in tandem with the centrifugal governor weights and springs on the crankshaft and will so by working in conjunction,and adjusted to be self compensating for a certain load applied.This is what a governor does of course,but when an hand throttle is introduced to adjust engine speed ie to make the boat go slower or faster another tension spring pulling against the natural float of the governor and so over rides it up to maximum revs when the governor takes over again to prevent over revving, All these springs of different weights and strengths have to work in careful harmony,quite a delicate balance if the governor is to operate properly.

[claudia]

I just want to say how much I appreciate all your efforts to help me cheers all, some more info.There is only a trace of smoke on idle I assume would be expected on a engine of this age. when out of gear it will rev way up to what I think is maximum, I certainly would not want to run flat out for long. Yes there is a point where when underway that it will not go any faster and thats when the black smoke appears if I move the throtle forward nothing happens if I bring it back to just over tickover the smoke goes but the boat slows down. The prop was brand new from Midlands chandlery so should be right one if its the right one for my set up remains to be known. If nothing else this is a facinating insight into the world of injection systems, just wish I knew what engine I have now.

[bizzard]

I just want to say how much I appreciate all your efforts to help me cheers all, some more info.There is only a trace of smoke on idle I assume would be expected on a engine of this age. when out of gear it will rev way up to what I think is maximum, I certainly would not want to run flat out for long. Yes there is a point where when underway that it will not go any faster and thats when the black smoke appears if I move the throtle forward nothing happens if I bring it back to just over tickover the smoke goes but the boat slows down. The prop was brand new from Midlands chandlery so should be right one if its the right one for my set up remains to be known. If nothing else this is a facinating insight into the world of injection systems, just wish I knew what engine I have now.

Ian it sounds like maybe your expecting too much of your set up,these engines are only of moderate power but torquey nevertheless. And your boat with an SR2 correctly propped would only be capable of about 6or7 mph flat out.

[claudia]

I would say 3-4 is my lot

[Chris Pink]

Ian it sounds like maybe your expecting too much of your set up,these engines are only of moderate power but torquey nevertheless. And your boat with an SR2 correctly propped would only be capable of about 6or7 mph flat out.

 

6-7 mph is asking a hell of lot from an SR2 on a narrow boat on a canal, you'd be pushing to get that on a 30 foot boat on a river.

 

If the boat is starting to smoke somewhere in the rev range then yes, the propellor is too big but if you've cycled behind an (older) bus going up hill it's the same thing.

 

There may be gearbox losses but a lot of the more esoteric diagnoses on the thread are not going to be achieved by a non-mechanic.

 

To go any further it would be necessary for an experienced person to see the boat.

 

my next test would be to see how easily the engine turns over from the prop shaft with the decompressors open, see if there's some drag in the gearbox. (spanner on the shaft coupling)

 

Ian - have you PM'd Chris-B - or even rung Marine Engine Services? Have you found any numbers on your engine? This ID will pin it down to the propellor size.

[bizzard]

I would say 3-4 is my lot

And at this 4mph maximum is the engines exhaust chucking out lots of black smoke,if yes i'd say its either over propped and possibly you have an SL or LR engine.As long as the gearbox and propshaft all turn freely that is.

3to 4mph is a brisk walking pace,can you overtake walkers or do they all overtake you?

 

Or is this a Lister SR2 powered Ferrari GT Berlinetta.

Edited December 15, 2011 by bizzard

[bizzard]

6-7 mph is asking a hell of lot from an SR2 on a narrow boat on a canal, you'd be pushing to get that on a 30 foot boat on a river.

 

If the boat is starting to smoke somewhere in the rev range then yes, the propellor is too big but if you've cycled behind an (older) bus going up hill it's the same thing.

 

There may be gearbox losses but a lot of the more esoteric diagnoses on the thread are not going to be achieved by a non-mechanic.

 

To go any further it would be necessary for an experienced person to see the boat.

 

my next test would be to see how easily the engine turns over from the prop shaft with the decompressors open, see if there's some drag in the gearbox. (spanner on the shaft coupling)

 

Ian - have you PM'd Chris-B - or even rung Marine Engine Services? Have you found any numbers on your engine? This ID will pin it down to the propellor size.

It depends on the underwater bow shape.If this is fine and sharp as a lot of older boats were ie Harborough ,''i had one''7to8 mph is no trouble with an SR2.

[Timleech]

I would say 3-4 is my lot

 

Is there a massive difference between top engine speed in gear, and out of gear? You should expect a small difference, but a massive one confirms that something is wrong in the prop size or maintenance departments.

 

Tim

[bizzard]

The main difference in power between the SR2 and LR2 is gained by a longer stroke than the LR and possibly the SL, The bore diameters are the same 3.1/2''plus slightly different valve events to match. So in this case the SR2 should have slightly longer cylinder barrels making that engine slightly taller.Ian you need to find another boat with an SR2 and take some measurements and compare.

The SL i'm not sure how they gained the extra power over the LR. Probably stroke again.

 

Incidentally the injectors in the SR are different to the LR's and probably the SL's and not i'm almost sure interchangeable.

So if you buy my 2 SR injectors which are definitely SR ones and they don't fit then its certainly not an SR.

If you take one out Ian and photograph it and stick the pick up on here i can compare it with the real one,if its the same you have an SR. But be careful and take your time doing it.

 

THE PROBLEM IS ALMOST CRACKED!!!!, i think. HOORAY.

Edited December 15, 2011 by bizzard

[bizzard]

The main difference in power between the SR2 and LR2 is gained by a longer stroke than the LR and possibly the SL, The bore diameters are the same 3.1/2''plus slightly different valve events to match. So in this case the SR2 should have slightly longer cylinder barrels making that engine slightly taller.Ian you need to find another boat with an SR2 and take some measurements and compare.

The SL i'm not sure how they gained the extra power over the LR. Probably stroke again.

 

Incidentally the injectors in the SR are different to the LR's and probably the SL's and not i'm almost sure interchangeable.

So if you buy my 2 SR injectors which are definitely SR ones and they don't fit then its certainly not an SR.

If you take one out Ian and photograph it and stick the pick up on here i can compare it with the real one,if its the same you have an SR. But be careful and take your time doing it.

 

THE PROBLEM IS ALMOST CRACKED!!!!, i think. HOORAY.

The injectors are of the single hole Pintle type but the length of the nozzle bodies is different in each type of engine.