I have google just about every site I can trying to find out what's going on. Situation: 96 3.0LX Mercruiser with Alpha/Gen 2, Merc carb. Carb rebuilt two years ago and in that interim, has ran like a scalded cat and idle was just about as perfect as you can get. Took it out this year, same thing. After about 2 hours riding around, started noticing idle problems. Had a heck of a time cruising through the no wake section of the docks and even harder time getting it on the trailer. But I did. Last weekend, took breather cover off and noticed that when it would die back down, there was no fuel coming from the horns, or whatever you call that, no fuel was dripping down the carb to the throttle plates. Hmmmm....adjusted the idle cam and finally got it to idle, but at about 1100 rpm and not exactly smooth. Adjusted the idle mixture screw, but not a lot happened. I cringed every time I put it in gear, but I had the wife, daughter and her friend in the boat so I just lived with it. Always 100% gas, no ethanol stuff. Dropped a can of seafoam in the gas tank, and sprayed a whole can of carb cleaner down the throat and didn't really change anything. I did research that to get the idle "right", do the following.....back the idle cam screw out until it barely touches. Then, 2 turns. Seat the idle mixture screw, then turn 1 1/4 out. Also, I just dropped in new spark plugs and wires last weekend hoping that might help, but not really. The old plugs that came out were really dark, I think it's burning really rich. What puzzles me...since that carb was rebuilt, engine as been fine. Idle great, hole shots were smooth and powerful. Now, problems out of thin air. Even now with my home made idle fix, the hole shots bog down and when I kill the engine, it diesels everytime, even if I let it sit at idle for 2 minutes. When I took the breather off, the automatic choke flap was straight up, verticle. It has the electronic choke bevel on it. Really having a hard time with what all went wrong that quickly...I mean....could those two adjustment screws back off somehow from just cruising around? Everything else on that engine/boat work fine. New oil. ANY ideas where to look next outing would be greatly appreciated.
