high idle

[clasavi]

hi there. i have a 1998 mercruiser i/o 350 magnum efi that is idling high. while at the dock waiting for the engine to warm up it idled high but constant in the 1100 -1200 range.

after she reached proper temp i went for a spin. i ran the boat for about 5 minutes and she was fine. however, on my way back to the marina (no wake zone) i put her in neutral and the engine raved up to 1500. once i docked i cut the boat off. then i started it again she idled high but constant in the 1100-1200 range.

what could it be?


thanks in advance for any help

Claudio

 

[mpdive]

Re: high idle

First thing I would do would be to remove the cable and see if it returns to idle. You wanna make sure your cable is not binding. Other suspects would be the IAC motor(idle air control) or the TPS(throttle position sensor). I have found the TPS to be suspect more than the IAC. Best thing is to get a manual and follow the flow chart so that your not parts buying.