Help with Universal M25 Diesel - 1983 Catalina C36

[bomberhart]

I replaced the copper seals and took the old ones out.

It took 4-5 attempts of heating glow plugs, then turning over for 5-10secs before it would catch. Then it would take 2-3 starts to maintain an idle. I would start with 1/3 throttle up and heating the glow plugs for 10 secs off of a small solenoid bridging the wire from the control panel and pulling power from the positive terminal on the starter.

[jimbunyard]

Did the engine sit up for a long time in it's recent life?

If you're sure that there are no vacuum leaks in the suction side of the fuel system (fuel wouldn't be obviously leaking except possibly when the engine is off), then the problem sounds more like an injection pump or governor issue.

For the injection pump either internal sealing issues or sticking p&b(s), on the governor/governor linkage a missing, broken or stretched spring or corroded governor bearings. Either of these conditions would be best diagnosed by an experienced on-site mechanic.

As an aside to the previously mentioned 'specified' idle speed, I still think 700-800 rpm is the appropriate idle for a small engine, and know that shifting at 1200 is detrimental for the gearbox, so an easy workaround would be to set the idle at the lower speed, shift at that speed and then immediately run up to the appropriate speed to avoid chatter. And then of course remember not to run the engine in gear at less than the 1000-1200 speced by Universal...