Lumpy Yanmar 3GM30 Raw

[Jabamusic]

Following a recent engine-out I have it all reconnected and it runs fine except at idle speed when she is lumpy and no where near as happy as before. Once the revs are raised she motors beautifully.
She starts just as before (i.e. no problems) and no sign of smoke - although a very small drop of oil out of the exhaust on startup (and I mean small).

Any thoughts? I have had it suggested it might be injectors (or the injector spray pattern), equally valve tolerances and a list of other possibilities (which at some point will probably include a visitation from Martian mechanics with a penchant for messin!).
As always, your ideas/thoughts gratefully received.

BTW what is the correct idle speed for a 3GM30?

Jaba

 

[robbieg]

Idle speed is about 850rpm

Check you idle is set at the right speed=850 to 900rpm should be about right. Have you had her reconditioned and if so have you bedded in the new rings and bores?-Normally about 5-10 hours motoring

 

[Jabamusic]

No not reconditioned - it was a problem with the gearbox that's all.

I believe that the idle speed is in that range.
Thanks