3.0 Merc flooding?

[ShearerLuck]

I have a 1987 VIP with a 3.0 merc I/O. It is a little "cold blooded" but will crank right up at the dock, however, after she warms up and I shut it down to drift awhile it floods when I try to start it. I have used come compressed air on the air filter and that has not helped. Once I do get it running, it will idle rough until I can throttle up, and after a couple of revs it will idle just fine? any ideas before I take it to the shop?

 

[MCarson]

Re: 3.0 Merc flooding?

mine did this, had a blown gasket between the accelerator pump nozzle/venturi post and air horn. Might try looking down the throat of the carb when you shut it off. If you see gas dump down there when you shut it off, that gasket is bad, might as well rebuild the carb at that point.

 

[dhammann]

Re: 3.0 Merc flooding?

This is a common problem for this year. The float level specs were incorrect, the level needs to be lowered. Due to the inherrent vibration of this engine at idle the foat valve will open intermittently causing the float bowl to overfill and flood. This causes rough idle and hesitation on acceleration until the level drops to the correct level again. Also this year had a incorrect airhorn gasket....excess gasket material interferes with the float causing it to hang (at idle)