Briggs float needle leaking

da.bees · Nov 29, 2017

Craftsman LT1000 917.271840 W/21HP Briggs,carb#693479
Origional tuel tank beneath seat leaked so I mounted another small tank on hood. Engine started running rich and flooding. I replaced the float needle and fuel pump diaphragm but flooding continue's. I didn't notice a way to renew seat for needle. My questions. Do'es raising tank above carb increase pressure that fuel pump supply's against needle? Should needle seal well enough to hold added pressure if it is indeed more than it was origionally?

Married2Allis · Nov 30, 2017

The needle seat must be corroded or gummed up. Soak the seat area with carb cleaner for a while. Them with the carb off, dab a mild abrasive like comet in the seat then take the new needle and rotate it back and forth in the same manner as you would lapping valves. Then flush the carb out completey.

T.R.K. · Nov 30, 2017

to answer your question, yes height does matter. The higher the tank is, the more pressure on the needle valve.

That said, if its only an additional foot or so, it should not make a difference. The fuel pump can develop 1 to 2 psi, itself.

I don't have a parts book close-is this the carburetor with the plastic seat and float assembly in it? If so, renew the little o-ring around the seat/between the seat assembly and the carburetor body. If that o-ring is cracked, gas completely bypasses the seat.

If the seat is in the carburetor body itself, lap the seat using a Q-tip. I wouldn't use the new needle because you may damage it and that would compound your original problem.

Also, some of those carburetors are available aftermarket very reasonable priced.

da.bees · Nov 30, 2017

The reason I'm trying to salvage carb is because new is over $200 on Ebay. Thanks for the tips on dressing the seat. I hadn't tried it before because I feared damaging the viton needle tip.

tractorguy2 · Nov 30, 2017

You could have dirt in your fuel tank. Or your new needle doesn't mate with the seat. My B&S shop says to use toothpaste as a grinding compound to mate the two surfaces. I use a small fuel line hose and stick it over the end of the needle for a spinner handle.

If the side walls of the seat have groves wore from the up and down movement of the needle. The needle will not seat correctly and the carb will need replaced.

da.bees · Nov 30, 2017

Thanks everyone,as suggested,I polished the seat and the leak stopped.

Briggs float needle leaking

da.bees

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Married2Allis

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T.R.K.

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da.bees

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tractorguy2

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da.bees

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