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Discussion Starter · #1 ·
We own a Subaru RGV12100 Genset that has a fuel delivery issue.

I was raised on a farm, so, if you wanted it to run, you had to learn how to work on it. The "fuel pump" incorporated into the design of this particular genset, on the other hand, has me scratching my head.

The issue began when I noticed a fuel leak, which was a bit surprising considering that this generator, which we purchased brand new, hadn't been used very much. After a bit of research in the parts manual, I identified that the leak was coming from the fuel pump. After speaking to a friend, who works on small to medium gas engines to supplement his income, I was warned to watch out for what he called "pulsed fuel pumps."

Apparently, this type of fuel pump is driven, at least in part, by pressure coming out of the engine's crankcase. This allows the pump to deliver more fuel when RPMs increase, a good thing, but it also means that there's an open line between the crankcase and the pump -- and that means that a defective fuel pump can cause fuel to flow into the engine's crankcase.

It turned out that my friend was correct because we found fuel in our engine oil.

Long story shortened (a bit), I don't really feature this "fuel backfeed" shortfall of the OEM fuel pump design. I was wondering if anyone else on the board has gone through this issue and, more importantly, what was done to rectify this particular flaw. I was thinking about installing an inline electric fuel pump, but regulation becomes an issue with this solution.

Our genset will run fine without a fuel pump, but the engine suffers fuel starvation under heavy loading, which, I assume, is why the fuel pump was installed in the first place. Has anyone else modified their genset to run on a low-volume electric fuel pump and, if so, what did you do about pumping too much fuel at low engine RPMs?

Thank you for your time ...
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