f-12 fuel pump question

F-12 guy · Oct 24, 2012

TI have a f12 I have been working on, I'm haveing trouble
with fuel pump. When I turn gas on at tank the fuel strainer
fills up and then gas will start to run out vent on bottom left
of pump body if you are looking at pump on tractor. My gas
lines are clean. I can crank on tractor and gas will slow to a
drip coming out of pump but starts back soon as I stop.
Thanks for your help. Josh

Dave Allgire · Oct 24, 2012

You need to replace the diaphragm. The vent in the lower left is on the bottom side of the diaphragm. The top side of the diaphragm has fuel on it. The only way to get fuel where you say it is coming out is the diaphragm is shot. Also, if you are getting fuel there, it is also going into the crankcase. You might want to think about changing your oil also.

Craig45 · Oct 24, 2012

Just rebuilt my pump and it is an easy job. Parts kit is available from Rice equipment in Clarion Pa. They will ask you what the check valves look like so you get the right kit.

LenNH · Nov 2, 2012

Can't add much to the above, but here are some musings on the fuel pump issue.
I grew up with 3 F-12s. The fuel pump diaphragms back in the 30s and 40s were not as good as today's diaphragms. Eventually, you could expect a diaphragm to split. The F-12 was an incredibly reliable and durable tractor, and I have always thought that the fuel pump was its only weakness. The use of updraft carbs on most rractors might have been an admission by the engineers that they didn't want to cause the owner problems down the road by fitting a fuel pump. They may have thought a downdraft carb was worth the potential problem.

f-12 fuel pump question

F-12 guy

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Dave Allgire

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Craig45

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LenNH

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