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1990 351 Sport Nautique dies in idle after heating up

Deano007

New member
So I am hoping someone can help me solve the nagging problem I have been having with my old but good boat. It has 660 hours and has been religiously maintained, but for the past two years has been stalling in idle after about two riders worth of use. It will idle rough and then stall and need to sit for about 20 minutes before starting again. I have replaced the coil, resistor, rotor and cap. It does not seem to be fuel related as the jets are spraying fine during stalling. Are there any other electrical components that might cause this problem?
 
Ayuh,.... If this is a carbed motor,..??

My 1st guess is, the idle circuit in the carb is plugged up,....

If so,... Tear-down, 'n rebuild the carb,....
 
So I am hoping someone can help me solve the nagging problem I have been having with my old but good boat. It has 660 hours and has been religiously maintained, but for the past two years has been stalling in idle after about two riders worth of use. It will idle rough and then stall and need to sit for about 20 minutes before starting again. I have replaced the coil, resistor, rotor and cap. It does not seem to be fuel related as the jets are spraying fine during stalling. Are there any other electrical components that might cause this problem?


Does your carb's venturi jets continue to put out gas after stalling? If so, have you found the solution to your problem? I am trying to solve a similar problem with my neighbor's 1979 351 Nautique. It has a Holly carb that at very slow idle the carb is dripping too much gas out the primary venturis. When it dies or gets shut off, you can watch gas continue to come out of the venturis for 10 to 15 seconds. This, of course, floods the engine making it difficult to start until it cools off (20 minutes). He can get it started in about 10 seconds by opening the throttle all the way and cranking it, as this is standard deflooding procedure for carburated engines. I'm a car hobby guy that has rebuilt probably 100 carbs over the years and I examined his Holly carb and everything inside looked OK, but replaced the float and float valve needle and seat anyway - it got a little bit better but still has the problem. If this sounds similar to what you are seeing, please let know if you found the source of the problem. It seems that gas is getting past the float valve or the fuel pump has too much pressure - not sure if that's possible.
Dave
 
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