B&S 42A777-E1 DiaphragmverFuel Pump Issues

[jeckel7234]

Hi all,

I have a B&S 42A777-E1 18.5hp motor on my riding tractor. This motor has a diaphragm style fuel pump that is integrated into the body of the carb, Ive had massive issues with the ability of this pump to pull a vacuum on the fuel tank.

Every 2-3 mows, (during the season 2-3 weeks) i have to rebuild the fuel pump, most of the time i really can just pull the springs and diaphragm out and reinstall to get the motor to work. As i go to crank over the mower I notice that fuel is not flowing through the fuel filter as well as ive verified little to no suction where the fuel line connects to the fuel pump.

I took the springs out of the fuel pump and bought a low pressure/low flow fuel pump off ebay with the hopes that i could bypass the diaphragm pump. I could the motor to start but not stay running for longer that a few seconds.

Does anyone have any suggestions or ideas for a more permanent fix?

Thanks,

 

[Tinkerer200]

Might start by checking that the gas cap vent is not plugged, leave it partially loose and see what happens.

Walt Conner

 

[Luffydog]

Might also check intake gaskets and the breather tube as well cracks in the tube will cause an air leak and poor suction leading to bad fuel delivery. As well as what tink said.

 

[bertsmobile1]

And while we are throwing random suggestions without any thoughts of a proper diagnosis check for a good fuel flow from the tank cause if the outlet is plugged with debris ain't nothing gunna suck fuel through it.
And as you say this is an ongoing problem my $ would go on that one or on loose fuel lines sucking air.

 

[Luffydog]

What I was thinking bad fuel del.

 

[Boobala]

Just out of curiosity, have you cleaned or rebuilt the carburetor itself, ?? ( I'm thinking a float needle issue )
if fuel CAN'T get past the needle or is restricted for some reason, everything in FRONT of it stops, it sorta backs-up ( kinda like a clogged sink-drain ?? )
I'm sure you already have the shop manual, .. But here's a copy in case ya don't ............

https://drive.google.com/file/d/0B6NaqjIxWV1ybHphbUNTQUNNR2s/view