Fast Idle

[Bert]

My 1999 150 Johnson won't drop down to slow idle when it warms up. It has been working fine, when it reaches the correct temperature, the RPM's drop to the correct idle speed. Started the boat today and the RPM's would not drop once it warmed up.
Need suggestions on what to do.

 

[JUSTINTIME]

Re: Fast Idle

fuel injected?

 

[Bert]

Re: Fast Idle

No, it's carburated.

 

[R.Johnson]

Re: Fast Idle

Check qwik-start with a timing light, and see if it is dropping back.

 

[Walker]

Re: Fast Idle

Are you sure your motor warmed up enough? Heck I'm in S. Texas and on these cool days and cooler water temps mine takes several real minutes to warm up and drop out of quick-start.

 

[Bert]

Re: Fast Idle

Walker, it's coming up to temperature, I just resolved an over heating problem and have been using an infared gun to verify that the temp gauge is correct. I'm going to check the temperature sensors in the head to make sure they are working. If the one that sends the lower temp is not working the idle won't drop.

 

[Walker]

Re: Fast Idle

First check the white w/black stripe wire from the temp sensor and make sure its connected and not broken ar frayed or grounding out somewhere.

 

[Bert]

Re: Fast Idle

Checked the temp sensor today and its fine, not sure what to do next.