Engine Problems

[aznewsh]

I have a 1977 24' Searay cuddy cabin with a small block chevvy and volvo outdrive.

I have replaced plugs, leads, cap, cleaned and reset points to 16 thou, tested at 32 on dwell meter so everything seems well electrically now.

I have had the Rochester Quadrajet carb rebuilt by a mechanic I trust.

The engine ran great for about 20 minutes then just seemed to loose all power, sounds like it is trying to run too rich, closer inspection of the carburetor seemed to support this theory at least in the idle chambers.

Question is why would a newly rebuilt carb be flooding like this, the mechanic who rebuilt this is an older mechanic who has done lot's of this kind of work and works full time as a mechanic, i have no reason to doubt his skills, he is a neighbour and a friend. Where should I look for the problem? and why wouldn't he have spotted it when he rebuilt it? he rebuilt it in his garage not in the boat so was unable to test it.

Other points of note, the engine really struggles to idle at any less that 10 and seems to vary on the tach quite wildly, up to 2 or 3 either way.

Any thoughts?

[gonzo]

Carb is overflowing. Either the float is set too high or the needle valve is not closing properly.

[yokebutt]

Az,

Could be as simple as something dislodging in the fuel line when you worked on it and ended up in the carb.

Yoke.