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Mercruiser 454 with Webber 4BBL wonbt hold idle

J

jkleban

Guest
"My mercruiser occasionally wo

"My mercruiser occasionally won't hold an idle. If I bring the idle up to 750 RPM the engine will tend to idle between 725 to 775, and gradually drop off to under 500 rpm, or stall. When it drops to 500, I will goose the throttle up to 750. The engine will then ease up to 11-1200 rpm on it's own. If I bring it down again, it will repeat the same. The carb is Webber 4bbl with electronic ignition. Purchased new 1 year ago. This does not happen all the time. Sometimes it idles perfectly, hot or cold. Any Ideas?"
 
"The boat is one year old? Tak

"The boat is one year old? Take it back under warranty.

Could be a lot of things- fuel quality, pressure, spark intensity, dirty flame arrestor. What have you checked so far?"
 
"Most likely the carb is simpl

"Most likely the carb is simply flooding. You can tell for sure by slowly turning in the idle adjustments (motor warmed up and idling). If the motor doesn't stall with the adjustments screwed all the way in, its rebuild time.

Jeff"
 
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