Any ideas as to why diesel engine wont rev past 2000RPMS`s?

[Karlsenkystfiske]

No way. I would hear it if the pump is running. Also the pump had variable vanes, so it does not do much in terms of loading up the engine unless some hydraulic equipment is running.

 

[lustyd]

But I dont understand it at all. The control cable is putting the control arm in the same positions as I do by hand :S
Once I connected the control cable it is not reving past 2000 RPM`s! Makes no sense to me.

Definitely weird. With the cable attached, what happens if you also push it by hand? I realise you said it's against the stop, but occam's razor would suggest there must be something wrong with that cable, given you've demonstrated that the engine works just fine.

 

[Karlsenkystfiske]

With the cable attached I am not able to push it. There is to levers attached to it, and a few meters of cable, so I am not able to manipulate its length. Yess I agree with you about the razor Oh well, good things is the motor is running nicely.

 

[B27]

I don't know this engine.
But generally:
If it won't rev, it's either overloaded, not getting air, or not getting fuel.

If it's overloaded or not getting air, expect black smoke as excess fuel isn't burned properly.
IF it's not getting enough fuel, either the injector pump is not being supplied, or the injector pump is not pushing the fuel in.

IF the injector pump is not putting fuel in, that's either a knackered pump or the controls are wrong.
If it's more modern, with electronics, then it's RTFM time and/or look for help with diagnostics.

Useful diagnostics might include a turbo boost gauge and measuring the fuel pressure supplied to the injector pump.

 

[scottie]

Is there a reason that you won’t investigate the control

 

[PaulRainbow]

I don't know this engine.
But generally:
If it won't rev, it's either overloaded, not getting air, or not getting fuel.

If it's overloaded or not getting air, expect black smoke as excess fuel isn't burned properly.
IF it's not getting enough fuel, either the injector pump is not being supplied, or the injector pump is not pushing the fuel in.

IF the injector pump is not putting fuel in, that's either a knackered pump or the controls are wrong.
If it's more modern, with electronics, then it's RTFM time and/or look for help with diagnostics.

Useful diagnostics might include a turbo boost gauge and measuring the fuel pressure supplied to the injector pump.

Did you read post #18 ?

Thought not.

 

[jamie N]

I don't know your engine at all, but if the control arm is in the same position each time, and only operates 'normally' with the control cable disconnected, then (logically) the control cable must be affecting 'something' between the throttle lever and the control arm, be it either mechanical or electronic. Does the throttle have any attached sensor that might go to an engine management component?
I wish you luck.

 

[penberth3]

I don't know your engine at all, but if the control arm is in the same position each time, and only operates 'normally' with the control cable disconnected, then (logically) the control cable must be affecting 'something' between the throttle lever and the control arm, be it either mechanical or electronic. Does the throttle have any attached sensor that might go to an engine management component?
I wish you luck.

Another thought. You've also got a speed governor within the pump? Unlikely to go wrong but could cause odd behaviour with engine speed?

 

[PaulRainbow]

I don't know your engine at all, but if the control arm is in the same position each time, and only operates 'normally' with the control cable disconnected, then (logically) the control cable must be affecting 'something' between the throttle lever and the control arm, be it either mechanical or electronic. Does the throttle have any attached sensor that might go to an engine management component?
I wish you luck.

My thought exactly Jamie. That cable must be doing something else, or the control lever is.

 

[PaulRainbow]

Another thought. You've also got a speed governor within the pump? Unlikely to go wrong but could cause odd behaviour with engine speed?

Again, see post #18 ?

 

[vas]

v.odd, obvs don't know the engine and 2page spec sheet not particularly helpful:

Fuel System:
Proven and reliable Mechanical Governor

brand and model of the control thingie?
elaborating on @jamie N , maybe in parallel to the manual operation, there's a "security feature" and if a potentiometer doesn't show that the lever is where the cable says to the governor, ECU takes over and drops revs?
Tbh far fetched and I'd congratulate the engineer who thought of such a stupid thing, but cannot imagine anything else that would mess a mech governor other than some electronic subsystem failing.
Cannot really be anything like water in fuel, over/under boost, temp, fuel press as that would affect the engine in manual operation as well...

Coming to think of it, I'm probably typing bull as that should also affect the manual no cable operation??? v.v.odd!
please do come back and let us know what it really was, v.curious!

V.

 

[Alex_Blackwood]

With the cable attached I am not able to push it. There is to levers attached to it, and a few meters of cable, so I am not able to manipulate its length. Yess I agree with you about the razor Oh well, good things is the motor is running nicely.

Do you mean There are TWO levers . If so what does the other one do??

 

[PaulRainbow]

OP mentions hydraulics, and it's a fishing boat, so will have systems most of us are not familiar with. I wonder if there is a connection to the hydraulics, perhaps the lever also controls some sort of "governor" for the hydraulics, stops them overloading the engine ?

 

[scottie]

Perhaps we shouldn’t get any more speculation it not good for o wellbeing

 

[Alex_Blackwood]

OP mentions hydraulics, and it's a fishing boat, so will have system most of us are not familiar with. I wonder if there is a connection to the hydraulics, perhaps the lever also controls some sort of "governor" for the hydraulics, stops them overloading the engine ?

Could be Paul, Maybe the engine does more than just propulsion? Perhaps we don't have the whole picture, drip feed of information?

 

[penberth3]

Could be Paul, Maybe the engine does more than just propulsion? Perhaps we don't have the whole picture, drip feed of information?

Er, read the first post.

 

[Zing]

When you rev the engine in neutral, presumably the test in post #18 you are not putting a load on it. It might rev easily to oblivion even if it's not healthy. But load it up in gear and the fuel demand can go up by as much as a hundred times, so a very different situation. A fuel flow restriction under load would be the most obvious explanation I can think of for the problems you are having. I'd check the filters, and fuel lines first. Blow the lines clear and change filters if needed, then check out the lift pump for correct functioning and a leaking diaphragm or check valve is another failure point to investigate.

 

[vas]

from his post reporting this incident it's implied that it's in gear as he's mentioning full pitch. I'd expect an experienced fisherman knows that in neutral it goes up to hell rpm easily

 

[PaulRainbow]

When you rev the engine in neutral, presumably the test in post #18 you are not putting a load on it. It might rev easily to oblivion even if it's not healthy. But load it up in gear and the fuel demand can go up by as much as a hundred times, so a very different situation. A fuel flow restriction under load would be the most obvious explanation I can think of for the problems you are having. I'd check the filters, and fuel lines first. Blow the lines clear and change filters if needed, then check out the lift pump for correct functioning and a leaking diaphragm or check valve is another failure point to investigate.

In post #18 the OP states "No hesitations even with full pitch applied."

He states in post #1 he's done the filters.

 

[wombat88]

I know nothing but does the OP's engine have a turbo with VVT (variable vane turbo)? They can get gunked up if the engine is not thrashed on a regular basis.

I have experienced some quite weird things with a VW marine engine thus equipped.

Will get my hat.