The Boating Forum - gas gauge acting up

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View Full Version : gas gauge acting up


mames19
05-21-2012, 08:50 PM
my gauge is stuck on empty, i have tested power, which is good. i also jumped the wires on sender, goes to full, i pulled the sender out of the tank, slowly moved the float and the gauge moved, i also put the float in a bucket and it floats.

i feel like ive covered all parts, but when i put it all back together it still reads empty, with half a tank of gas, any ideas?


TTaxi
05-21-2012, 10:01 PM
It sounds like you covered this when you jumped the sender unless you just jumped the gauge sender terminal to 12V+ to make it read full. But if the gauge is grounded to the tank check to confirm the tank is still wired to a GOOD ground. And for the heck of it runa jumperfrom the sender flange to the neg post of the same battery that powers the gauge.

In response to your moving the float arm, did the gauge needle move gradually up and down scale or did it go from near empty to full or have a dead spot in the middle? Sometimes cheaper senders will wear on their resistance rub plate and have blank spots that will not allow the gauge sender circuit to ground out through the sender to tank at those gas levels, so gaue reading is lost.

And sometimes the float end of the arm will get hung up on a tank side or baffle, though the purposely- irregular 5-screw fastener spacing pattern is usually oriented so as to prevent that . In your case the float would have to be held in the down position.

Also keep in mind if that was water in the bucket, that water has higher specific gravity than gasoline (by ~+50%???) so a bad sender float may float in water but not in gasoline.

If the sender does need replacing, FWIW I'd suggest in order of preference :
-Centroid Products -no moving parts, easy cut to length, calibratable for Full and user-preferred Empty, capacitance-based thin-tube sender with good reliability and steadiest gauge readings ,( 1st choice by far), or...
-Rochester ( also under Moller and maybe other brand names) pretty reliable mechanical/magnetic swing arm sender with included tank top gauge( can be read if batteries are in the boat & on or not) plus the optional attachable electric gauge sender module, (much more reliable than typical swing-arm types, though still has a fair amount of gauge needle movement. No electric circuit in the tank, only lever and gears and magnet to affect the external gauge and module .) , or...

WEMA vertical float sender.

I'd advise against the ubiquitous fairly cheesy "Universal" adustable swing-arm types.

Birdman will say tank senders and gauges are worthless but they are indeed are a darn good thing to have when a flowmeter totalizer does not get reset at fill or, on some fuel management gauges like my Floscans and redundant B&G NetEngineSystem , if the tank is not fully filled when totalizers are reset. Unlike the Bird's lifelong very sad sender experience (;)) , some of us do have senders that have lasted about 22 yrs and still going strong (Rochester, and never had any trouble with the excellent Centroids in 10 yrs on my old boat). I do log everything relating to fuel as Bird does , but still value the tank gauges.



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