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Tan, MerCruiser Certified Technician
Category: Boat
Satisfied Customers: 11076
Experience:  40 yrs. experience with complete engine repairs both inboard/outboard and MerCruiser Certified Technician.
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My boat wouldn't crank the other day. I ran 1 battery dead

Customer Question

my boat wouldn't crank the other day. I ran 1 battery dead and almost the second. I poured gas down the carb. still nothing. I noticed the venturis in the carb dripping fuel. after an hr it crunk and ran good for 2 hrs. I shut it off several hrs and it crunk back. on the way back to ramp it started sputtering then died as I was trailering. it hasn't crunk since. I put spark tester on coil and it's firing. I changes water seperating filter no water was in the gas I poured out. pulled 3 plugs 2 were wet 1 wasn't it was the fwd plug. any ideas. I also disconnected gray wire on coil but no change. it tried to motor once but it was blowing back through carb.2000 5.7 mercruiser thunderbolt ignition
Submitted: 2 years ago.
Category: Boat
Expert:  Tan replied 2 years ago.
Hello. My name is ***** ***** checked in the carb after it won't crank? Remove the flame arrestor and open the throttle to wide open look dome in the carb do you see puddled fuel?
Customer: replied 2 years ago.

it's definitely wet down there. the carb isn't dripping since I ran it the other day. but if I pour gas into the bowl it will drip out the venturis. I really don't want to rebuild the carb. I bet that is where you are going right?

Expert:  Tan replied 2 years ago.
Yep the carburetor is flooding. Whet happens is you geyt the engine started because the engine isn't flooded then the carb starts pouring fuel into the intake flooding causing the plugs to foul out. Once the plug get drenched with fuel the engine will not start. The only way to fix this issue is to remove the carb, disassemble, clean and install a carb kit. The inlet beedle is stuck open allowing the fuel fill fill the float bowl then over flow into the engine.
Customer: replied 2 years ago.

is this a #39 mercarb I don't see the tag on it. really was hoping I wouldn't need to rebuild the carb. I'm trying to sell the pos.

Expert:  Tan replied 2 years ago.
Could you post the engine serial number please?