I need some help on this. The M51A2 auxilary fuel tank and the drivers side tank. I see the pump and on the other tank, no pump. On the dash is a switch that says rite fuel tank or left fuel tank. also on the dash is a switch that says fuel transfer pump. How does the fuel get pumped from aux. tank across to the drivers side tank. And why two switches? I checked my manuals and do not see anything explaining the system and how it works. I thought that it was a pump in each tank, and one pumped into the other as the first tank got low, when you activated the transfer switch? I am wondering if something is missing?Besides my brain??? I took pictures of the dash switches and each fuel tank. Can someone explain how this works?Looks complicated.
Interesting, for comparison, my dual tank 757 does not use a transfer pump, but has check valves and a selector valve for returning the return flow to the tank that it's running on. It does have one pump in each tank also and one single "left" or "right" selector. No need to transfer fuel from one tank to another...
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Bjorn
MEP-018A (needs new generator head)
Avatar: XM757 in OK prepared for 1,000 mile trip home. Part of 6,000 mile journey in 2006.
1968 M49A2C modified with 1960 M756A2 truck bed and 1975 HIAB 765A knuckleboom, exhaust brake, VIC-1 and more.
1969 Ford XM757 8x8, 5-ton Pershing 1A truck tractor...the "improved MV".
"Some things can't be made better, just differently......a lot of things actually"
My m62 that was converted from a gasser to a multi, has a transfer pump from the small passenger side tank to the larger drivers side tank. It is mounted in between the passenger side tank and the battery box area. Not too hard to follow the lines to it. I have not yet checked to see what the left tank - right tank switch does, but mine is set up like yours too.
On the 800 series the dash switch for L and R is just selecting which tank is reading on the gauge. Don't know if it has any relevance to your problem but I do see you do have two sending units. Also my 818 has a selector valve on the floor to actually select which tank to draw from. Seems the system in yours draws from one tank only no matter what. You just pump fuel from the aux to the main to use the fuel in the aux. As to where the aux pump is I don't know but the parts manuals do have great exploded diagrams which may help you.
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Chuck Graham
1969 Kaiser-Jeep M35A2
Auxilary fuel tank pump?
