1500 max rpm? nhc 250

[tiny110]

I have tried changing the fuel filter. I have readjusted all the linkage for the throttle. But even I just couldn't the stops in the injection pump. And I have tried turning up the fuel pressure. I am running good clean fresh diesel. I have put 200 gallons of clean fuel through the truck. It does not matter which gear I am in it will not push over 1500 rpm.

Is there some type of governor on the truck?

 

[Csm Davis]

Yes there is a governor but I would unhook the linkage on the fuel pump and see if it will go higher by hand and if not mark the arm and shaft so to put it back in same position and try moving it to see if it has slipped I have had one that had rotated on the shaft

 

[tiny110]

I have already tried that. The shaft is rotating in hitting both stops correctly. The throttle has full range of motion.

 

[wreckerman893]

Unless something is restricting the flow of fuel other than a clogged filter you may have a pump issue.

There is also the possibility that it's sucking air into the line somewhere.

 

[tiny110]

Yea but it don't matter if I'm in first gear or fifth it will not go above 1500 rpm. I would think if it had a clogged lines or air getting it sucked into the line. It would change depending on the load on the motor. I'm going to go outside and try reading it in natural. So I can see if it will get above 1500 rpm with no load.

 

[bearboley]

Did you shim the spring in the back of the pump to increase pump pressure? Those shims also control high rpm. The more shims the higher the rpm's and pum pressurre.

 

[seano11]

Are you sure your tachs not just off and your really hitting the limiter

 

[tiny110]

No i did not shim the spring. The tachs not off.

But i just went out and was playing with the fuel screw and i guess i unscrewed it to far. How bad did i mess it up?

 

[Stalwart]

The another possibility is a bit more likely, you have the pump from a 50Hz generator Diesel engine. 1500 RPM would be the correct RPM for a Diesel engine turning a 4 pole head for 50Hz. For 60Hz you use 1800 RPM.

 

[tiny110]

Even the rpm on a gen is adjustable.

 

[Stalwart]

Yes I just did mine, 50Hz to 60Hz! But a generator pump isn't the same as a vehicle pump. If you have the wrong pump it won't work the same. Since you know everything, please leave the rest of us on SS out of it.

 

[tiny110]

I work as a marine electrician. So I might know something about generators. Maybe your generator is as special as you are. Lol

I guess I will have to make some phone calls and get some help.

 

[doghead]

Did you change the filters, or just look at them(as you posted before). I personally can't see a 10 micron particle.

 

[diverman555]

Check your emergency shut off at the pump, could be restricting fuel.

 

[doghead]

Check your emergency shut off at the pump, could be restricting fuel.

I think that was mentioned in his other thread. (this is why we continue one thread about a specifict issue/topic).

 

[diverman555]

didn't know he had another thread, my bad.

 

[bearboley]

Why get insulting when someone was trying to help you out?

 

[quickfarms]

Have you checked and or replaced the air filter?

 

[73m819]

This is the same guy that wants instant go fast to 70 mph from his 818 on 1600s pulling a loaded trailer, does not want to HEAR that dumping the 1600s just might be a BIG help in more ways then one

 

[Stalwart]

Yea but it don't matter if I'm in first gear or fifth it will not go above 1500 rpm. I would think if it had a clogged lines or air getting it sucked into the line. It would change depending on the load on the motor. I'm going to go outside and try reading it in natural. So I can see if it will get above 1500 rpm with no load.

He said it all right there. Only the injection pump can limit the engine RPM under ANY load. No other problem will limit the truck to 1500 rpm in 1st and 5th, he just doesn't want to listen since he knows it all. I hear he worked on a boat once.