# John Deere 300 Industrial Tractor - fuel pump issues - gas engine



## ronfaux (8 mo ago)

I thought I previously posted but lost that post so I am reposting.
I have a 1973 JD300 Industrial tractor with loader, had multiple fuel issues but have narrowed down now to the fuel pump. Having initially replaced the original fuel pump per the parts manual part numbers (Original gas fuel pump part # was AR52158 and diesel fuel pump was AR52159.) The replacement pump went through a couple changes in part # however the result was the same part # for both gas and diesel. Ran into problems with the carburetor flooding out and gas running straight through carburetor. The service manual addressed such an issue and showed how and where to drill a relief hole in the original diesel fuel pump part #. However the new pump is not the same design. Concluded the fuel pump was over-pressuring the carburetor and causing the needle valve to not shut off the gas flow to carburetor. By chance, putting the old fuel pump back on it seemed to work correctly but in short order it just pooped out. Took it off and put the new pump on only to have the same flooding problem. Not believing the original pump is rebuildable I attempted to cut the fuel pressure with a regulator. I now encounter the engine quitting when cutting back to idle position. I believe the carburetor is properly adjusted but problem remains. I am thinking the regulator is a volume flow regulator vs. a pressure regulator and not providing adequate fuel when idled down. Could this be the problem? I would like to put an OEM `fuel pump back on but cannot seem to locate the lower pressure gas fuel pump per the original part #. ANY IDEAS WILL HELP.


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## pogobill (Jan 31, 2012)

ronfaux said:


> I thought I previously posted but lost that post so I am reposting.
> I have a 1973 JD300 Industrial tractor with loader, had multiple fuel issues but have narrowed down now to the fuel pump. Having initially replaced the original fuel pump per the parts manual part numbers (Original gas fuel pump part # was AR52158 and diesel fuel pump was AR52159.) The replacement pump went through a couple changes in part # however the result was the same part # for both gas and diesel. Ran into problems with the carburetor flooding out and gas running straight through carburetor. The service manual addressed such an issue and showed how and where to drill a relief hole in the original diesel fuel pump part #. However the new pump is not the same design. Concluded the fuel pump was over-pressuring the carburetor and causing the needle valve to not shut off the gas flow to carburetor. By chance, putting the old fuel pump back on it seemed to work correctly but in short order it just pooped out. Took it off and put the new pump on only to have the same flooding problem. Not believing the original pump is rebuildable I attempted to cut the fuel pressure with a regulator. I now encounter the engine quitting when cutting back to idle position. I believe the carburetor is properly adjusted but problem remains. I am thinking the regulator is a volume flow regulator vs. a pressure regulator and not providing adequate fuel when idled down. Could this be the problem? I would like to put an OEM `fuel pump back on but cannot seem to locate the lower pressure gas fuel pump per the original part #. ANY IDEAS WILL HELP.


Welcome to the forum. Your post count is at (1) so maybe you forgot to hit the post button.
We have a few resident fuel pump experts that should swing by to offer assistance.


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