View Full Version : High Idle

06-24-2009, 11:46 PM
I have a 1976 90 hp chrysler OB that idles to high. Can anyone tell me how to adjust the idle. I have tried everything I know but can not get it to idle slower without manualy turning the distributor. Thanks

06-25-2009, 04:11 AM
"hey sean

let me first say i am not the "master mechanic" just a member giving you my 2 cents.

there are several things that can cause a high idle. it would help to know if you were doing any work on it or if this just started. have you looked at the spark plugs? do they look like they have in the past or are they kind of while?

like i said there are several things that can cause this, but what i would be concerned with the most would be an air leak. like a leaking seal in the bottom end for example. in your car, that just means an oil leak, but 2 strokes use the bottom end to mix the fuel and air and there is a lot of pressure and if a seal starts to leak then it pulls air in which will cause the motor to run lean or get to much air. this can cause the idle to be high and can cause it to over heat.
again there are several things that can cause the idle problem, if it were mine that would be my first concern. if you have moved the distributor, making it to far advanced will do the same thing. if the idle went down when you moved the distributor then you probably retarded it which probably won't kill it but it will have little power. remember heat kills motors.
i am not that familiar with your motor, and Glamb is the man you need to talk to.
if you want to check the seals and the over all condition of your motor do a leak down test on it. you can get a leak down tester at harbor freight for about 30. take a look at the plugs and make sure they aren't real whit in color.
good luck oh... if you don't have a manual, get one, without one you can cost yourself more time and money than buying two or three of them"

06-25-2009, 10:12 AM

Thank You! I was not aware of that. I will check for a leak."

Cliff C
06-25-2009, 03:14 PM

a old trick I learned as a tech years ago to fund vacuum leaks it to a simple propane torch turn it on don't lite it and pass it along where you might think a leak might be if their is one the motor will speed up if their is one."

06-25-2009, 05:03 PM

the propane will work, i prefer using wd40 or barrimans chemtool, but this will only check for vaccum leaks at exterior connections... what i was refering to was internal seals, like a crank seal etc... any air leak will have the same effect, cause it to lean out and get hot. like i said there are a lot of things that can cause it to idle high... check your spark plugs for being white, put the timing back where it should be even if it is to just dead time it, that will be close enough.

something simple to keep in mind. it takes three things for a motor to run, spark, fuel, compression. check them in that order and only work on one at a time. if it has spark and the timing is on, then move to fuel. you don't want to get yourself in a situation where you have two problems going at once or it makes it hard on you. The carb is pretty straight forward, before you start to make any adjustments look at the little things, choke closed all the way? is the throttle valve open or closed all the way and on both carbs, is everything tight... float bowls, nuts that hold it on, linkage etc... it is easy to miss something so don't think a second look is wasting your time, it isn't. and talk to graham lamb, he is the man. good luck.. see ya on the water"

Cliff C
06-25-2009, 05:10 PM
"Well said . "