1972 20 hp Johnson

"Good morning, I have a 1972 J

"Good morning, I have a 1972 Johnson 20hp. Problem: Engine starts fine. Seems to run fine. But seems to loose fuel pressure while running. (Soft bulb) Motor will just bog down and then after playing with the throttle pick back up. If I squeeze the bulb and pressure it back up it will pick up immediately and run fine again. I have replaced the spark plugs, fuel lines in the motor, fuel pump, gas line and bulb from fuel tank and the tank itself twice. Always making sure all connections are tight. Going from steel tank to plastic tank and back to a new steel tank. Have even taken it to local marine dealer. Who said it ran great in their tank. Any ideas?"

did you buy a pre-made fuel ho

did you buy a pre-made fuel hose and bulb or did you make your own? homemade could be excessively long.

how low does the tank sit below the fuel pump? gravity works.

when you replaced the pump did you check for obstructions in the air hole that supplies pressure for the pump? pressure could be to weak if either of the above items are a factor.

my fuel tank for the test tank was always at engine level. this could be the reason it ran fine on their tank.