Logo

fuel pump or carb float?? 1975 15hp

dawnfogg

Contributing Member
'75 15hp pull start Johnson. Put carb kit in and replaced slow speed needle after thoroughly cleaning carb. Engine idles OK, but when the power is advanced the motor will run for about 15 seconds but will then die. Neighbor who has go-kart experience says that it sounds like the engine is being starved. So, is there a way to tell if the problem is a bad fuel pump or maybe the float not adjusted correctly in the carb? Since I just rebuilt the carb, would prefer to eliminate the fuel pump before I take the carb apart agan.
 
Re: fuel pump or carb float??

Try pumping the fuel line bulb. If that overcomes the problem look at the fuel pump.

Id have thought it would run for longer than 15 seconds even if the fuel was shut off therefore i think I would be expecting to be looking at the carb again.

Generally speaking carb floats are parallel with the joint face when the needle valve is closed.

You might find some useful info HERE amongst the outboard motor related articles
 
Last edited:
Re: fuel pump or carb float??

I also heard you can put a clear hose between the fuel pump and the carb and see if fuel is being pumped. Thought I got the float parallel to the bottom as the kit showed, but not sure what else it would be in the carb itself.
 
Back
Top