Start-up High Idle

[Reming870]

Mercruiser 3.0L 1984. Electric Choke. Rochester Carb

When cold starting it will remain in High Idle (2000 RPM). It takes about 5-10 min before it cuts down to 700 RPM and I have to rev the engine to knock it down.

Is this normal? Its a real pain if I stop for awhile because I have to go through the whole exercise of waiting before I can move. I don't want to shift it at 2000 RPM and this happens everytime I let the engine cool.

If not normal, how do I adjust this?

 

[Don S]

Re: Start-up High Idle

Sounds like someone may have installed an automotive carb on it. The automotive version had a high idle cam on it.
If that is the case, you need to replace the carb. Non marine carbs are a serious fire hazard should the float stick.

 

[Reming870]

Re: Start-up High Idle

Engine ser# is 6829350
Installed Roch Carb is 7041139 05711R1.

I replaced the old carb (manual choke) with this one. The old one was definetly not the proper carb. The Rochestrer was new in box when I bought the boat last year.