Increasing idle a tad on engine - ok to do?

[fredrussell]

Since replacing engine mounts on my 3GM30 the engine feels a bit more ‘lumpy’ at idle in neutral and in gear. If you increase the revs very slightly (say, 850 to 950 rpm) it goes away. Any negatives to increasing idle 100 rpm at the engine?

 

[ridgy]

My 2GM idles at 950 and hasn't exploded yet. I sometimes think about turning it down but never get round to it.

 

[Alex_Blackwood]

Since replacing engine mounts on my 3GM30 the engine feels a bit more ‘lumpy’ at idle in neutral and in gear. If you increase the revs very slightly (say, 850 to 950 rpm) it goes away. Any negatives to increasing idle 100 rpm at the engine?

Perfectly OK to do that. In fact possibly beneficial as it may take the engine out of a vibration band that will cause other problems. Assuming that the new mounts are correctly fitted Had vibration problems on an engine that had been installed with too large a distance between the feet and the mounts. Kept breaking injector pump springs due to harmonics!

 

[LittleSister]

Since replacing engine mounts on my 3GM30 the engine feels a bit more ‘lumpy’ at idle in neutral and in gear. If you increase the revs very slightly (say, 850 to 950 rpm) it goes away. Any negatives to increasing idle 100 rpm at the engine?

Sounds a good plan. I can't see how it would harm the engine. It will be happier, as will you, if it is not thrashing around.

Note that you might not need as much as a 100rpm increase to make the difference, and that you rev counter might not be accurate, especially at low revs. (I think you can get a free or very cheap app for a phone to use its flash as a timed strobe to check the actual speed - though the engine running smoothly is more important than the precise number.)

 

[Laysula]

Just make sure that it goes in and out of gear ok.

 

[Minerva]

Sounds like a good plan to me; A wee play with the idle screw to get it idling smooth then a check to ensure gear box is still happy.

 

[fredrussell]

Many thanks all. I increased idle from an indicated 850 to an indicated 950 rpm and that was enough to remove the lumpiness.