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Issues with 351w PCM

Scott Wyss

New member
I have a 1981 Mastercraft with a ford 351w PCM motor. Started having problems our second time out this year and have not been able to isolate it, except pretty sure it is fuel related. Boat runs fine at idle and for the first 20 minutes or so, but starts to surge and cut out above 2600-3000rpm. So I replaced the fuel pump (mechanical), ignition coil, rotor and cap. The points and condenser were not changed. Rebuilt the Holley 4160 and boat still has the same issue. Gas is fresh, fuel lines are new and look good. Boat would die if give me trouble to restart, that went away after i rebuilt the carb. If I give it more gas when it starts to surge it clears up and runs fine.

When I rebuilt the carb, everything looked clean, no clogs that I could tell. I did not put it in chem dip just sprayed it real well with carb cleaner and blew it out with the compressor. Any ideas?
 
Ya still sounds like carb issues when cleaning carb do u spray into every port and passage and able to see where the cleaner exits, all jets removed and visually inspected there are a lot of cross drilled paths in carb that can easily have some junk stuck in it most carb has a few circuits idle which works fine for u and pilot or mid range and main jets for The mid- top end
So if just a small range dead spot something in carb sounds like still has some debris
 
I have a 1981 Mastercraft with a ford 351w PCM motor. Started having problems our second time out this year and have not been able to isolate it, except pretty sure it is fuel related. Boat runs fine at idle and for the first 20 minutes or so, but starts to surge and cut out above 2600-3000rpm. So I replaced the fuel pump (mechanical), ignition coil, rotor and cap. The points and condenser were not changed. Rebuilt the Holley 4160 and boat still has the same issue. Gas is fresh, fuel lines are new and look good. Boat would die if give me trouble to restart, that went away after i rebuilt the carb. If I give it more gas when it starts to surge it clears up and runs fine.

When I rebuilt the carb, everything looked clean, no clogs that I could tell. I did not put it in chem dip just sprayed it real well with carb cleaner and blew it out with the compressor. Any ideas?

Take a look at the anti siphon valve at the tank, looks like just a hose barb. I spent two summers chasing a cut out issue. Runs great after cleaning that %&@* part.
 
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