RRS GP-40 8 hp Kohler problem

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Marty_Knox
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RRS GP-40 8 hp Kohler problem

Post by Marty_Knox » Tue Jun 21, 2022 7:28 pm

I have a Railroad Supply GP-40 with an 8hp Kohler engine. If I leave it sit for more than a couple days. I end up with gasoline in the oil.
I make sure the valve on the gas tank is shut but I still end up with gas in the oil. Has anyone else experienced this? I plan on checking the fuel pump and carburetor, but any other suggestions?

ERIE S-1 BERKSHIRES
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Re: RRS GP-40 8 hp Kohler problem

Post by ERIE S-1 BERKSHIRES » Tue Jun 21, 2022 8:09 pm

Hey Marty the fuel pump is probably needing a rebuild ,very easily done and I would get a new shut off valve for the gas tank,It may still be leaking? fuel tank has a shut off so I must assume it's up in the air pretty high. not needed when you have a fuel pump on the Kohler the fuel tank should be setting on the frame of the locomotive or below the belly like a rail systems had!!.

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Marty_Knox
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Re: RRS GP-40 8 hp Kohler problem

Post by Marty_Knox » Wed Jun 22, 2022 6:48 am

First thing I did was change the shut off valve on the fuel tank. Yes the fuel tank is right up in the top of the shell.
I will get a kit and rebuild the fuel pump.

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ccvstmr
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Re: RRS GP-40 8 hp Kohler problem

Post by ccvstmr » Wed Jun 22, 2022 8:03 am

Hello Marty...

Have been running Don Phillip's Backyard Rails demonstrator A-A F7's for some 30 years (one unit powered, other unit a dummy). Like your GP unit, the F units had an 8 hp Kohler M8 engine. Never had a problem with fuel leakage as you described. The fuel tank sits on top of a redesigned hydraulic fluid reservoir...to increase oil capacity and fluid dwell time in the tank.

Number of years ago, put a 12 volt external fuel pump on the loco. Was thought that excess heat in the car body was the primary culprit for engine fueling. Have tried to increase ventilation under the hood.

Over the years, a number of upgrades/improvements have been made...mechanical, electrical and cosmetic. Like any machine, time and wear eventually catch up with these. Not sure this helps any. Just thought I'd share my experience(s). Carl B.
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jmurray
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Re: RRS GP-40 8 hp Kohler problem

Post by jmurray » Fri Jun 24, 2022 5:37 am

Marty,
Neols owned locomotive with the 8hp Kohler. Many people tried to solve the aledged overheating problems, and stalling out. They went as far as cutting a hole into the cab roof for ventilation, but no success.

I had an oportunity to operate the loco, and turns out it was starving for fuel, quie the opposite to your issue.

however, for a chance at it, I replaced the carb, and fixed the "overheat" issue.

so when the engine got hot, it expanded the carb hinge mounts enough to restrict float movement.

the float hinge has very close tolerances, I believe if it can stick open, it can certainly stick closed. what remaing fuel that beyound the shut off valve can certainly end up flooding the intake, which then weeps into the crankase via the valve stem.

your engine could run fine and not run rich while its idling or under power..but drips of gas is all it takes over time to get the results you are seeing.

maybe its not the carb, but a new one is approx $25, so It was worth a try..

good luck!
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Marty_Knox
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Re: RRS GP-40 8 hp Kohler problem

Post by Marty_Knox » Sat Jun 25, 2022 7:51 am

Carl, this was Bernard Leahy's. He bought it finished and painted from RRS in 1981. He added fans to it.
My Granddaughter Megan came with me to pick it up and claimed it was hers. She calls it the Mitten since it has the outline of the Lower Peninsula of Michigan on the cab sides.
John, I think I will replace the carburetor and fuel pump and see how it does.
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