1750 eratic rpm

[tom upton]

Picked up a 1750 diesel a while ago that had been sitting for several years. Some fresh fuel, filters and some tinkering and had it running, but rpm fluctuates at lower rpm's. Seems too run half decent wide open, but when at lower rpm especially if you let the clutch out that puts a slight bit of load on engine, rpm will drop by sometimes 5 or 600 rpm, sometimes going back up but not always. Both primary and secondary fuel filters were very dirty so I am wondering if some crap got into the pump causing some kind of fuel metering issue? I dont think there is a fine screen on the inlet to pump like some have, but is there anything the average guy that has never tore into a fuel pump can do to clean anything in the pump? It doesnt appear to have any fuel line leaks. The other thing I was wondering is it looks like the pump had been done just prior to it sitting as it is quite clean and high pressure fuel lines have been painted diffent colour than tractor, so maybe out of time slightly? Not sure if this would cause rpm flucuation though? It does start well and runs okish wide open. Maybe just put it to work to see if it clears up? Any suggestions appreciated.

 

[oliverkid]

That kind of RPM fluctuation out of a Roosa Master pump is generally an indicator that the governor flex ring is going bad.

 

[Dieseltech]

IF the pump has been recently repaired it sound like the metering valve is sticking. Add some two cycle oil to the fuel and use it, the extra lube MIGHT just make the trouble clear up.

 

[tom upton]

IF the pump has been recently repaired it sound like the metering valve is sticking. Add some two cycle oil to the fuel and use it, the extra lube MIGHT just make the trouble clear up.

Thanks Sounds like its worth a shot.