Mercruiser won't idle down when warm
 

Hi,
I hope someone can help with this. We just bought a clean 1984 SeaRay 19'
with a 3.0 140 Mercruiser. Everything is fine with the engine...BUT....once
warm it will not idle down. In neutral in runs up to 1400rpm and idles in
gear at 1000+...too fast for shifting or docking obviously. When cold it
idles smoothly at 700 rpm. I've checked the idle mixture screw and played
with it some...but the standard 1-1/4 turn out gives best result. Choke's
not sticking. am I over looking something?

Thanks,
Jim

Mercruiser won't idle down when warm
 

Hi Jim,

Maybe you have some air leaks in your intake system.

This is quite common on a 10 year old motor. There are rubber vacuum hoses
running everywhere on boats, RVs, trucks and cars. After some time they get
dried out and crack allowing air to leak into your system causing you motor
to run lean.

If you buy a can of starting fluid, you can spray it around the base of the
carburetor and around any vacuum lines. If the motor starts run ruff, you
have found a leak as long as it is not going into the normal air intake.

There are vacuum actuated little canisters that are for pulling off your
choke after the engine is running and you have one normally on your
distributor. These can get old and leak air too.

This can be a problem with all gasoline powered motors.

If you don't feel like this is something you want to handle, a good marine
mechanic can fix it for you.

--
Bill Kiene

Kiene's Fly Shop
Sacramento, CA
www.kiene.com

"Jim" wrote in message
s.com...
Hi,
I hope someone can help with this. We just bought a clean 1984 SeaRay 19'
with a 3.0 140 Mercruiser. Everything is fine with the
engine...BUT....once
warm it will not idle down. In neutral in runs up to 1400rpm and idles in
gear at 1000+...too fast for shifting or docking obviously. When cold it
idles smoothly at 700 rpm. I've checked the idle mixture screw and played
with it some...but the standard 1-1/4 turn out gives best result. Choke's
not sticking. am I over looking something?

Thanks,
Jim

Mercruiser won't idle down when warm
 

Make sure the fast idle cam is not sticking. If a Holley carb (probably not
on a MC) there is a vacumn activated fast idle lever.
Bill

"Jim" wrote in message
s.com...
Hi,
I hope someone can help with this. We just bought a clean 1984 SeaRay 19'
with a 3.0 140 Mercruiser. Everything is fine with the
engine...BUT....once
warm it will not idle down. In neutral in runs up to 1400rpm and idles in
gear at 1000+...too fast for shifting or docking obviously. When cold it
idles smoothly at 700 rpm. I've checked the idle mixture screw and played
with it some...but the standard 1-1/4 turn out gives best result. Choke's
not sticking. am I over looking something?

Thanks,
Jim