engine running rich

[caplbi]

1992 chris craft crowne has a 5.7 cobra,and king cobra drive. It also has a 4bbl holley carb and electronic ign.
Heres the problem. Starts up fine and idles smooth but i can smell gas fumes and see petro in the water from the exhaust.
This weekend i took the boat out for a spin, 15 min cruise in the lagoons to the bay. Once out in the bay the boat got up on plane with no problem running 32 mph (est) 4400rpms. ran for about 1hour then back to the lagoons to the house. I keep the boat at 1300 rpms in the no wake zone. About 2 houses from the dock the boat started running rough then died. had to wait about 10 min before it would start up again. once it started the fumes were noticable. any suggestions?

 

[bolo78910]

Re: engine running rich

turn in the two idle misture screws antil the engine rpm start to drop.

then back the screw out antil the rpm start to rise again, keep going antil it start to drop, then turn it back in .

in between where the rpm rise turn in and find the sweet spot for the smooths idle you can . that should help. remember you have to do both screws.

one first then go to the next. right now you are running rich so turning the screws inward will make it leaner. turning out from where you have it now will get more richer. good luck.

 

[bjcsc]

Re: engine running rich

Sounds like your carburetor needs to be rebuilt. Adjusting the idle circuit mixture will only affect the mixture at idle (hence the name). It has no effect on the running mixture. The running mixture is controlled by the jet size and clean, clear carburetor passages. If you haven't made any jet changes...

If you can smell fumes while it's running - STOP RUNNING IT. It could be the last thing you and anyone around you smells. Chances are it's the floats/needles/seats in your carb..Either rebuild it or have it rebuilt, but don't run it if you can smell gas for crying out loud.

 

[milkyway]

Re: engine running rich

If this is happening to you at idle and no-wake rpm? Make sure your idle mixture, idle speed and timing are correct. You have new plugs? Do you have gas showing up in the water only when idling or low rpm, or also at high rpm? Rev the engine at high idle to check if your carb is also dumping gas at high rpm.

Describe what kind of fuel pump you have so others will have more information.

Did you tinker with the carburetor lately? Is this the first incident? Have you done anything that might have caused this?