low fuel pressure?

[Hatch2002]

i have an 80's johnson 40 horse. it was used very little but it sat for years. i took it to a mechanic when i got it and he did the nessasary work to make it ready for use. he also replaced the vro with a standard fuel pump. i mix 50:1. motor starts and idles fine every time planes out fine. after about 5 minutes it acts like its not getting enough fuel and bogs down to a put. if you throttle back to about 25% it will sound like the second cylindar kicks in again and it will run.(at a put) IF at full throttle and you "pump" the cold start switch on the ignition as fast as you can it will run at full speed. i have pumped the bulb while its at full speed and its hard. yesterday i got the bright idea (wasnt very bright after all) to clean out the fuel pump while i was on the water. i dropped a spring and had to bypass the fuel pump to get back to the dock..... still had to pump or hold in the ignition switch in to get it to run at full speed while my wife pumped the bulb from the rear of the boat of corse. any help or ideas on this will save me a .357 round and my motors life i have scheduled it for exicution at sunrise

 

[schematic]

Re: low fuel pressure?

Hi
If squeezing the primer ball while running didn't improve performance, then it likely not a supply problem. Rebuild the carbs...

 

[Hatch2002]

Re: low fuel pressure?

i had the carbs rebuilt and cleaned last year but at this point not trusting the tech all that well. i have the original fuel pump with the oiler should i have it rebuilt? it was pumping to much oil and fouling plugs

 

[schematic]

Re: low fuel pressure?

If it runs fine when activating the primer, but runs poorly when only firming up the ball, it would rule out ignition and fuel pump. Its possible something is floating around in the carb blocking off the main jet periodically.