HOw do I test fuel sender and gauge?

[bota7800]

My B7800 fuel gauge reads between about 3/4 full and full, no matter what the actual fuel level is. The gauge reads zero when the switch is off. I suspect the sender unit.

Has anyone had this behavior? The only threads I found mentioned nonfunctioning gauges.

I need to determine which unit is wrong. How do I test the sender? I can put a multitester across it but what am I looking for?

Also, the only sender I ever replaced was in a Cessna which had easy access on the wing. How do I get to the sender on a Kubota?

How do I test the gauge itself?

If anyone has done this I would appreciate some pointers. Thanks

 

[carpenter383]

Does the guage move any? If not make sure the float isn't stuck.

Sounds like the sending unit is bad, test by grounding the ground wire going to it (from the guage) and see if the guage reads 0 with the key on. With no ground the guage should be on full.
That is typicaly the way most sending units work.

 

[bota7800]

Thanks

Yes, the gauge moves. It moves from full to 3/4 when empty. I will try to look at it this weekend.