Merc. V6 205, smokey idling, rough start after use. Carb adjustment?

[MacDan06]

Hi,

I have an '86 Mercruiser 4.3L V6/262. When I first put it in the water cold, it starts up right away without any help from the throttle. After that start up, every time after, it needs the throttle to be open 3/4 of the way, and it still takes a good 5-7 seconds of cranking to start up. I get a lot of dark smoke in those starts. There is also a lot of smoke coming out from the exhaust when I idle or at low speeds (so much that sometimes I open the hatch just to make sure it's only the exhaust and not the engine smoking). It runs well aside from this. WOT is a little low (about 4100 RPMs). The carb is a newly rebuilt 4bbl quadrajet, installed at the end of last season. I have also replaced the fuel pump, distributor, plugs, and plug wires all at the end of last season.

My thought is that the carb is just running very rich and the mixture screws need to be adjusted a bit, but thats just a guess. The boat GUZZLES gas. I realize it's a larger engine, but I can rip through 5 gallons in 20 mins riding WOT.

Any suggestions or diagnostic ideas would be greatly appreciated. Thanks.

 

[fuzzybob]

Re: Merc. V6 205, smokey idling, rough start after use. Carb adjustment?

My WAG is the choke is not opening. Take the top off the carb and start the engine cold, watch the choke plate.... it should be wide open in a few min.

 

[Bondo]

Re: Merc. V6 205, smokey idling, rough start after use. Carb adjustment?

The carb is a newly rebuilt 4bbl quadrajet, installed at the end of last season. I have also replaced the fuel pump, distributor, plugs, and plug wires all at the end of last season.

My thought is that the carb is just running very rich and the mixture screws need to be adjusted a bit, but thats just a guess. The boat GUZZLES gas.

Ayuh,... My WAGuess is,... Either the carb Rebuild was screwed up, or the carb just Ain't rebuildable...
Your problems are Much Deeper than just the mixture screws...