416- 8 onan powered

[Larcor69 3]

Just picked this up, changed filter, oil, lubed her up, ran great for about 10 mins, then started lopping, even under load, engine goes from 3000 rpm to 1800 rpm up and down, would this be caused by a governor or a dirty carb? Thanks

[ol550 827]

I'll vote dirty carburetor.

[Ed Kennell 35,767]

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[Larcor69 3]

I put some seafoam in gas tank, if it persists after another tank of gas, guess I will get a rebuild kit,  Thank you everyone 

[lynnmor 6,775]

If you let it cool down completely and then it runs normally till it warms again, that is a sign of a governor problem.   If you run the engine at high speed, say 3200 RPM, and then it overspeeds after warmup with no change in throttle setting, let me know.   But yes, clean that carb to rule out problems in there.  Often you can clean the carb without buying parts.

[Larcor69 3]

Just now, lynnmor said:

If you let it cool down completely and then it runs normally till it warms again, that is a sign of a governor problem.   If you run the engine at high speed, say 3200 RPM, and then it overspeeds after warmup with no change in throttle setting, let me know.   But yes, clean that carb to rule out problems in there.  Often you can clean the carb without buying parts.

 

[Larcor69 3]

Yes,  I let it cool off for about 20-30 mins and it ran fine, doesn't sound as if it over speeds at all

[WVHillbilly520H 10,369]

Might be the ignition module, does it back fire and die, then once it cools down it fires back up.

[Larcor69 3]

No, it runs just rpms go up and down