View Full Version : Carb problem

08-15-2005, 09:17 AM
Has anyone had a problem with their engine wanting to idle too high after it has been run real hard.

I Have a 1993 351 engine with the standard Holley Carburetor. Sometimes after I have run the boat really hard the idle rpms will be so high that I am afraid to put it into gear for fear of damaging the transmission.

If I shut the engine off and let it sit for just a minute or two and then restart the engine, it will usually idle normally.

Again this only happens when it has been operated at nearly full throttle conditions.

Any thoughts?

Kevin 89MC
08-15-2005, 03:42 PM
I'll jump in here only to say that my '89 does the same thing. This board is great - I'm sure we'll get some good tips!

08-15-2005, 03:53 PM
My '88 acts the same as well. I've always just assumed that it does this because everything has been recently lubricated, primed with fuel, hot spark plugs, good air, that the motor is at it's optimal operating condition immediatly after running at high RPM's. Hence the brief increase in idle speed.

How high are you talking, skilew? Mine will go from about 740 (out-of-gear) to 800 (out-of-gear). If you are go to around 1,000 or above after running hard, then something may be sticking open in the carb someplace.

And, yes you can damage the tranny by engaging above 1,000 RPM's. If you are higher, definitely let it settle down before heading into gear.

08-15-2005, 04:27 PM
Yeah, something may be sticking. Make sure your choke is open. If it sticks closed or partially closed it can cause your idle speed to be high. If your linkages are loose it could cause the problem too. But it really sounds like a stuck choke


08-15-2005, 05:36 PM
The engine idles up around 1200 RPMs. I checked the choke and it is not sticking closed. But I have not checked the secondary side. Since this only happens after WOT I am thinking it must have something to do with the secondaries.