johnson 1978 4hp

[rtpogo11]

hello to everyone my question i have a motor that will run smooth when the bulb is hard on tank the motor starts pooping out when bulb goes soft is it the carb or the fuel pump if it is the fuel pump any idea thanks

 

[Vic.S]

Re: johnson 1978 4hp

If you can keep it running by pumping the bulb then suspect the fuel pump or air ingress into the fuel line.

Check also that there is no restriction to the fuel pick up from the tank and that the tank vent is open especially, if the bulb is tending to flatten.

Checked the filter on the pump?

 

[rtpogo11]

Re: johnson 1978 4hp

i have the service manual but iam not sure how to check a fuel pump do i just look at it see if it looks good i had the motor running on another tank it did it once and awhile on that tank and hose but that is a yr ago