I've been fighting a fuel issue and am totally baffled this evening. Here's the story -
After a full engine build, the boat ran great, idled great, but would lose fuel pressure above 2800 RPM. I installed a pressure gauge and verified that the pressure was dropping. I rebuilt the mechanical fuel pump and seemed to solve the problem. The boat ran real good and would run wide open up to 4200 RPM and maintain good pressure (4-5psi). Then one day, it started sputtering while in a turn and died. It wouldn't restart. It was backfiring through the carb(fuel related), and seemed to be vapor locked. It started right up and ran good in the driveway once it cooled off.
Last year at Algonac, I started it, let it run a few minutes on the trailer, and after about 5-10 minutes, it died and wouldn't restart. Same symptoms, sputtering, backfiring, etc. I blamed it on ethanol fuel boiling as I could hear it sizzling in the carburetor. I replaced the mechanical pump with an electric one, and didn't get back out last year due to my big house project consuming the rest of Summer. I started it to Winterize it, but that was it.
I brought it home yesterday and started it tonight. It started fairly easily, but ran a little rough, then seemed to straighten out and was running pretty good. After a couple starts and restarts, it would barely idle and quit running again. It wouldn't restart and acted the same way again. I took the flame arrestor off and there was fuel vapor coming out of the primaries and the secondary flaps were completely closed and covered in fuel. I tried to start it again and it was the same issue, vapor in the primaries and fuel would bubble out of the secondary squirters and cover the secondary flaps. It seems like it was vaporizing/boiling fuel again, but nothing was hot, I could touch the intake, exhaust, block, risers, everything without much problem. After Algonac last year, I siphoned the entire tank and drained it nearly dry and put fresh Shell gas in it yesterday, so I don't think it's a gas issue.
Why would the carb be getting so hot with such little running time on it? Would a bad PCV valve allow hot air to flow into the base of the carb? I'm grasping at straws here, but don't know what else to do and need to get it fixed before going to Algonac, I'm leaving for Northern Michigan on June 15 and spending the week before the show at my in law's cottage.
FLASH1969 Chris Craft Cavalier Ski-230 HP 327Q
CCABC Board of Directors Member