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ProStar Slalom
06-03-2013, 07:21 AM
'84 PCM 351 with Holley 4160. This happened a couple of times last season and again this weekend. Started the boat and engine was running rough and rich with a lot of smoke, acting as if cold...didn't want to warm up. I thought maybe the choke wasn't working, but it opened fine as designed. A couple of re-starts and same thing...didn't want to idle, but with some additional gas would run, but still rough and would not smooth out. Let it sit for a couple of hours, come back and it starts and runs like a top; no issues. Same thing a couple of times last year. Any ideas? Thanks for the help....

ProStar Slalom
06-04-2013, 07:26 AM
Anyone...?

j.mccreight@hotmail.com
06-04-2013, 07:48 AM
Is your carburetor flooding?

thatsmrmastercraft
06-04-2013, 10:29 AM
If your choke is wide open after 90 seconds and not the problem, I would look for debris in the carb not allowing the needle and seat to close fully allowing too much fuel to enter the carb. When this happens, I would remove the flame arrestor and carefully look down the throat of the carb. You will likely see a large amount of fuel entering the carb that will continue to flow for a bit even after the engine is shut off. You are probably in need of a carb rebuild.

ProStar Slalom
06-04-2013, 06:09 PM
If your choke is wide open after 90 seconds and not the problem, I would look for debris in the carb not allowing the needle and seat to close fully allowing too much fuel to enter the carb. When this happens, I would remove the flame arrestor and carefully look down the throat of the carb. You will likely see a large amount of fuel entering the carb that will continue to flow for a bit even after the engine is shut off. You are probably in need of a carb rebuild.


Thanks for your thoughts. I concur. No telling how old this carb is, and plenty of gunk built up. But the darn thing runs great 99% of the time so I hate to mess with it....

thatsmrmastercraft
06-04-2013, 06:15 PM
Thanks for your thoughts. I concur. No telling how old this carb is, and plenty of gunk built up. But the darn thing runs great 99% of the time so I hate to mess with it....

If you do find too much fuel and suspect debris, you can always remove the primary fuel bowl and clean it out, replace the needle & seat, check the float adjustment and reassemble with a new blue reusable bowl gasket.

ProStar Slalom
06-05-2013, 08:06 AM
Thanks to all for the help. I've got some tinkering to do with the carb it seems...willing to give it a shot based on other recent threads about carb adjustments.

thatsmrmastercraft
06-05-2013, 09:51 AM
I had a similar problem on the first day of a weeks vacation a few years ago. Launched the boat and everything was fine. After a quick run across the lake to the dock, it idled terrible. Popped the flame arrestor off and saw fuel still coming out of the secondary side of the carb. Remover the secondary fuel bowl and there was a small piece of debris not allowing the needle & seat to close. Removed it, put the secondary bowl back on (thank you reusable gaskets) and was good for the rest of the vacation. Perhaps it took me 15 minutes to take care of.