rookie_j

are marine distributors vacuum advance?


thinking out loud; coming off throttle, vac advance sticks, shut engine off, distributor goes back to idle???? or did i just waste a couple braincells?

JUSTONCE

good thought, some may be but mine is centrifugal (MSD). I had thought that may be the problem though, weights hanging up after swinging out or something? but we've come to the agreement advance won't make the Idle go up that high.

aero-offshore

I have a stock electronic merc dist and a thunderbolt ignition, so mine problem is not distributor advance. Also I'm using dart alum pro one heads with no thermostat

JUSTONCE

Well It turns out it was a combo of timing and vacuum. I found a small vacuum leak in the carb gasket. This brought the idle up to about 1100, well the advance weight return springs I was running were too light so at that rpm it alwready began advincing to about 18 degrees. This took the idle the rest of the way up to 2000.

aero-offshore

Good job, but that dos'nt explain mine or possibly others, ours returns to normal when you shut it off then restart.

JUSTONCE

I still think you're guy's issue may be the timing weights not returning fully to base timing. When you shut down. they retract the rest of the way. Take a timing light with you next time it does it keep it running and throw the light on just to see.Worth a shot no?

aero-offshore

No timing weights, stock electronic merc distributer, advance is in the box.

JUSTONCE

I forgot you said that, I'm sorry. I guess my find doesn't help you. But its got to be in timimg or lean mixture from a vacuum leak. If you shut it down than restart, will the idle stay down or sit low for a min. than start to climb? I think that was part of my vac leak. cause if I shut it down and restarted it the idle stayed right for a little bit. Prolly just cause It was loaded up from the restart and than richened up the motor enough to cancel the vacuum leak for a few seconds till the motor cleans up.

aero-offshore

Nope, mine will idle right where it should and stays untill the next time I run it hard.I'm leaning to a sticky pcv valve? I duno.

aero-offshore

It must be some kind of vacuum thing, something sticking then when the vacuum goes away it returns, kinda like Just Once's sticky mechanical advance theory.