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

[JOHNPEET]

From what the OP has stated in post #18, it would strongly suggest that the engine itself is absolutely fine and points towards the control cable or control mechanisms as being the root cause of his problems. As we don’t know the detail of how or what exactly operates the cable, then it’s back with the OP at the mo.

 

[Alex_Blackwood]

Er, read the first post.

Yes, more than propulsion! So with both? levers connected?? is the other one having an effect. as said in #41 ball is in his court at the moment.

 

[Karlsenkystfiske]

I tried to replicate the experiment by removing the control cable and having the pump go all the way to max rpm by hand. Did not happen! So something else Is tricking me.

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

I am not that educated in how these pumps work. Engine speed is very stable.

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.

Had gunked up vanes on my TDI Golf back in the day. Filled it with mr muscle oven cleaner foam. Freed them right.
The turbocharger on the John Deere is a lot loss complicated. No vacuum, no variable vanes, no wastegate... Its just a blower

 

[Karlsenkystfiske]

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

What control?

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.

By control thingie you mean control cable?

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

They do the same thing. Just from different positions. Control cable from lever 1 to lever 2, then another cable from lever 2 to the control arm on the pump. The most basic of control systems

 

[PaulRainbow]

What control?

By control thingie you mean control cable?

No, the control levers. Logic suggests there must be something else connected to one of the levers/cables etc. or post #81 makes no sesne.

 

[JOHNPEET]

I tried to replicate the experiment by removing the control cable and having the pump go all the way to max rpm by hand. Did not happen! So something else Is tricking me.


I am not that educated in how these pumps work. Engine speed is very stable.


Had gunked up vanes on my TDI Golf back in the day. Filled it with mr muscle oven cleaner foam. Freed them right.
The turbocharger on the John Deere is a lot loss complicated. No vacuum, no variable vanes, no wastegate... Its just a blower

Are you saying that at this time, with the cable detached from the injection pump and by operating the pump lever by hand, with full pitch applied, you now can’t get the engine to run at full RPM?

 

[Alex_Blackwood]

Are you saying that at this time, with the cable detached from the injection pump and by operating the pump lever by hand, with full pitch applied, you now can’t get the engine to run at full RPM?

+1 Totally confused. What pump is the OP talking about, I assume he means the injector pump, or perhaps the hydraulic pump? He says "Engine speed is stable" Impossible to give a proper answer. Has he tried separating his two levers and seeing if the problem occurs with only one connected?

 

[QBhoy]

Hi. Just off the top of my head and after watching that video..if she was of the era to have an old school boost actuator…I’d be blaming that. But I’d say it’s more likely that you have instead an ecu controlling such things on a modern thing like that. That being the case…I’d absolutely be looking towards a boost sensor being to blame. Or perhaps even the control/wiring/sensory item’s associated. To me that looks to be gaining boost very very quickly, for an engine that’s not under load. Seriously quick build of rpms there..then a decline/loss or regulation of it there after. Maybe good idea to have a wee look into boost sensor issues or control issues, known previously or not, on similar units. That’s where I’d be at anyway.

 

[Alex_Blackwood]

Hi. Just off the top of my head and after watching that video..if she was of the era to have an old school boost actuator…I’d be blaming that. But I’d say it’s more likely that you have instead an ecu controlling such things on a modern thing like that. That being the case…I’d absolutely be looking towards a boost sensor being to blame. Or perhaps even the control/wiring/sensory item’s associated. To me that looks to be gaining boost very very quickly, for an engine that’s not under load. Seriously quick build of rpms there..then a decline/loss or regulation of it there after. Maybe good idea to have a wee look into boost sensor issues or control issues, known previously or not, on similar units. That’s where I’d be at anyway.

Then why did it work when he removed the cable and went direct to the throttle lever. Or did you not read that bit? Or am I just mistaken?

 

[Karlsenkystfiske]

Are you saying that at this time, with the cable detached from the injection pump and by operating the pump lever by hand, with full pitch applied, you now can’t get the engine to run at full RPM?

Yess. cant say what made it go to full RPM last time.

+1 Totally confused. What pump is the OP talking about, I assume he means the injector pump, or perhaps the hydraulic pump? He says "Engine speed is stable" Impossible to give a proper answer. Has he tried separating his two levers and seeing if the problem occurs with only one connected?

Nothing to gain from that, as you can see that the control arm on the fuel pump is in max position. The levers and control cables are moving as they should.

Why would I talk about the hydraulic pump? It is electricaly controlled. And trust me, I hear if it is doing something,

 

[scottie]

Yess. cant say what made it go to full RPM last time.


Nothing to gain from that, as you can see that the control arm on the fuel pump is in max position. The levers and control cables are moving as they should.

Why would I talk about the hydraulic pump? It is electricaly controlled. And trust me, I hear if it is doing something,

Do you have throttle control lever in dual (2) position to allow the engine speed to be run up,for when your hydraulic system is working or similar

 

[Karlsenkystfiske]

No. Just cause I need to operate the boat from inside and outside. Engine does not slow down when hydraulics are being used. Pump and engine is kind of matched together

 

[QBhoy]

Then why did it work when he removed the cable and went direct to the throttle lever. Or did you not read that bit? Or am I just mistaken?

I’ll admit to not picking that part up. So is that the case right enough ? And the current situation for sure ?

 

[scottie]

No. Just cause I need to operate the boat from inside and outside. Engine does not slow down when hydraulics are being used. Pump and engine is kind of matched together

No you don’t have dual control or yes you do and can change engine revs from inside and outside ?

 

[Karlsenkystfiske]

I have two control positions.

 

[JOHNPEET]

Yess. cant say what made it go to full RPM last time.


Nothing to gain from that, as you can see that the control arm on the fuel pump is in max position. The levers and control cables are moving as they should.

Why would I talk about the hydraulic pump? It is electricaly controlled. And trust me, I hear if it is doing something,

Ok. If you can’t repeatedly operate the injection pump lever with the cables disconnected and the engine operating as it should, then the problem is with the engine and nothing at all to do with the control cables or levers etc. They were only mentioned because we thought the engine was operating correctly with them disconnected.

Need a bit more info on the engine then. Is this a pure old style mechanical injection type engine? Does it have an ECU? I think you’ve already stated that the turbo is a basic unit without any fancy controls etc? Can you operate the injection pump lever without any load repeatedly, and does the engine make full RPM whilst doing so? Repeat with load and what is the outcome? Important to know that so that we can consider whether the governor is working as it should.

 

[Poecheng]

Would this assist?
Separate the control cable from the pump lever (as you have done already and found you can get full revs) then get someone to operate the control levers (which will move the cable, which is disconnected at the pump end) and, if there is anything secretly being controlled by the movement of the control levers, it still should be operative and reduce the max revs to your 2k limit. This would flush out what others have suggested above.

Thinking about it, you can put the lever(s) into WOT position with the cables disconnected and just move the pump lever yourself;

I suggest this as you have told us that with cables disconnected you can get max revs by hand but I have assumed the cable levers were simply left in neutral until the cable was connected to the engine again.

 

[JOHNPEET]

Would this assist?
Separate the control cable from the pump lever (as you have done already and found you can get full revs) then get someone to operate the control levers (which will move the cable, which is disconnected at the pump end) and, if there is anything secretly being controlled by the movement of the control levers, it still should be operative and reduce the max revs to your 2k limit. This would flush out what others have suggested above.

Thinking about it, you can put the lever(s) into WOT position with the cables disconnected and just move the pump lever yourself;

I suggest this as you have told us that with cables disconnected you can get max revs by hand but I have assumed the cable levers were simply left in neutral until the cable was connected to the engine again.

In post #43, the OP has stated that at a second attempt, he was unable to get max RPM with the cables removed and by operating the injection pump lever direct.
Suggesting that the problem may be intermittent!

 

[Poecheng]

In post #43, the OP has stated that at a second attempt, he was unable to get max RPM with the cables removed and by operating the injection pump lever direct.
Suggesting that the problem may be intermittent!

Yes I see what you mean (depending on what "It did not happen" means) but.....OP may, in fact, have done what I suggested and left the control levers in the WOT position but not attributed to the result to that circumstance ?

I think Paul first suggested a non-cable link between the problem and the levers in #51 and obvs after #43 so, it could be that the different results for the 'same' experiment was because it was not the same at all and that the OP had the levers in different positions but not considering whether that might make a difference as the cables were disconnected.

 

[scottie]

When you move the inside lever does the outside follow?
how many levers inside and how many outside
is gear selection avaliable outside?