What idle RPM?

[mathiasmorgan]

I have a 1969 250 cu. in. 160 HP Mercruiser (GM) straight 6 cyl. I'm still getting the boat seaworthy.. The engine runs great, but according to the tach it idles at around 900-1000 RPM, which seems pretty high to me. It could be that the tach is off, but by ear it sounds accurate. What should be the idle RPM for this engine? Anyone know?<br />George

 

[galaxy]

Re: What idle RPM?

Should be around 600-750.

 

[magster65]

Re: What idle RPM?

The drives like to engage at as low of rpm as possible and the engine likes a higher rpm to keep good oil pressure, vacuum and fuel atomization. I wouldn't go less than 600 rpm and not more than 800 or so in gear idling.

 

[mathiasmorgan]

Re: What idle RPM?

Thanks guys! That's what I'll adjust it to...