M4900 Fuel Petcock Position ??

Magicman

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Equipment
M4900 Utility Special 4WD e/w FEL & 1530 John Deere
Oct 8, 2019
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Brookhaven, MS
knotholesawmill.com
My M4900 Operator's Manual shows two fuel petcock positions: Off - horizontal, and On - vertical. The fuel petcock on my 2005 model M4900 has 3 positions: horizontal, vertical, and on around to CCW horizontal. It was CCW horizontal when I got it which is where it still is, but I wonder about the other two positions. ??

Maybe vertical is "On" and around to CCW horizontal is "Reserve", but I don't want to guess. ??
 

GeoHorn

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Equipment
M4700DT, LA1002FEL, Ferguson5-8B Compactor-Roller, 10KDumpTrailer, RTV-X900
May 18, 2018
1,778
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Texas
I know exactly what you’re decribing..... as my M4700 is the same way. It’s been two years now but I’ll try to report what I can recall about it...
When I bought it (used from it’s 2nd owner with 300+ hrs) .... one of the first things I did was address a fuel-drip at the exit of the fuel filter/valve body. The WSM suggested turning the fuel lever to the “off“ position ...exactly as you described. It didn’t turn the fuel off and I found I had to clamp the inlet hose to stop the fuel flow.
I cleaned the filter and then disassembled the valve to find that it was assembled incorrectly... there was NO WAY it was going to turn the fuel on or off. (Here’s the fuzzy-memory-part)... There is a ”spring-washer-ring” inside the valve that places the petcock against the sealing surface and it was assembled by someone previously out-of-order. I analyzed it and put it back together as I thought it SHOULD be .... and now it works as described in the Owner’s Manual. The 3-positions are now Off/On/Off depending where that lever is Placed.

BTW... the fuel leak was caused by the exit-elbow which is “press-fit” into the filter-body. Vibration loosens it and fuel leaks at that joint. I cleaned the elbow and the filter-body with electronic cleaner (carb cleaner should also work but I’d be careful about that plastic filter-bowl) and epoxied it into position with that wonderful elixir........JB-Weld. Let it cure overnight, I then lubricated the bowl and O-ring with silicone-grease and put it all back together. No further problem with leaks or valve.