Fuel pump rebiuld and or float adjustment.

madolive3

Petty Officer 2nd Class
Joined
Sep 2, 2011
Messages
120
I'm in the process of getting my old 78 115 Johny running and thanks to this forum It's running pretty good but i still have some issues. It seems to be running pretty well in the tank but it is smoking heavily, I'm sure way too much, my neighbors will testify to this. I know it's running very rich. When I pump up the bulb I can hear fuel seeping in one of the carbs and I have direct control of the fuel spraying in the carb by the amount of pressure applied to the bulb. The bulb gets hard but I can continue to squeeze and push fuel through the pump. Also, I am getting fuel pouring out of the lower carb ONLY right after I choke during start up.
I have already rebuilt the carbs and they were spotless inside, changed the floats, gaskets ext. I'm thinking that the fuel pump has a leak and is allowing , 1. the float chamber to over fill when I pump the bulb, and, 2. it's allowing fuel into the crank case making excess smoke and creating a rich condition after it starts. Am I correct in thinking that the bulb shouldn't pass fuel into the carbs? Also, the only way for fuel to get into the carbs from the bulb would be through a perforated diaphragm in the pump?? Could this kind of pressure from the bulb be enough to open the float valve and allow too much fuel in. Starts up pretty easily with a little choke. Thanks again.
 

JDusza

Ensign
Joined
Apr 21, 2009
Messages
997
Re: Fuel pump rebiuld and or float adjustment.

The bulb should push fuel to the carb. That's the idea of priming. The bulb will force fuel past the pump in order to get fuel into the carb to start. After it starts, the bulb may appear to go soft. That is usually OK as the fuel pump takes over.

What's your fuel mix ratio? Sounds like you have too much oil in the mix. Mix up a batch of fresh fuel to be sure.

What is "gaskets ext"?

J
 

lmuss53

Lieutenant Junior Grade
Joined
Sep 9, 2008
Messages
1,227
Re: Fuel pump rebiuld and or float adjustment.

Short answer is it is probably not the fuel pump. I would say it's a poorly set float, or one that has the plunger attached/installed wrong. I think your carbs (at least the leaky one) have to come back off.
 
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