'59 Johnson 18hp

[Ordneb]

My 1959 Johnson FDL13 18hp with a two line fuel system won't stay primed. When I pump up the tank the bowl will stay full indefinitely. But, when I start the motor, it will not keep the bowl primed. I have replaced the fuel and air lines and the tank gasket. Do I have carburator problems? Thanks for the help. How hard or expensive is it to convert to a fuel pump and single line system?

 

[alden135]

Re: '59 Johnson 18hp

If you re-title your post to "1959 Johnson" it might get one of the vintage motor guys' attention.(Joe Reeves, Paul Moir etc.) There are also a few posts in the search function relating to that changeover.

 

[krb113]

Re: '59 Johnson 18hp

I'm sure you know the filler cap on the tank needs to be tight to keep the pressure up. But you could have a bad seal on it (the tank top, not the tank gasket). If you don't get a good "hiss" from it when you open after trying to run/sitting in the hot sun, then you need to check on the gasketing under the primer/filler part of the tank. That is where the pressure from the engine comes into the tank and acts as the fuel pump. If it is bad, it won't hold the pressure