Fuel guage won't drop below 1/2

jwiebe

Cadet
Joined
Jan 6, 2011
Messages
6
I have an old Penn Yan and the fuel guage works fine between Full and 1/2 but does not drop below 1/2 indication. Found out the hard way while Striper fishing off of Nags Head. Any suggestions on what the problem might be?
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,758
Re: Fuel guage won't drop below 1/2

1) Does the gauge go to "E" with the key off? (Yes or No)
2) If you know roughly how much fuel is in the tank, disconnect the wire (normally pink) from the center terminal of the fuel sender in the tank (or at the "S" terminal on the gauge).
3) Measure the resistance between the sender and ground. If you disconnected the wire at the gauge measure between the wire and ground. If you disconnected the wire at the sender, measure between the SENDER and ground.
4) A full tank of fuel should measure 33 ohms, 1/2 tank = 109 ohms, and empty = 240 ohms.

Therefore, if you have more than 1/2 tank of fuel the readings should be somewhere between 33d and 109 ohms. Any less than 1/2 tank would still read roughly 109 "IF" the sender arm was stuck or there was a sender issue that prevented the arm from lowering more than 1/2 tank.

DO NOT replace the gauge as gauges are rarely the problem. If this test is inconclusive, pull the sender and check it manually.
 

jwiebe

Cadet
Joined
Jan 6, 2011
Messages
6
Re: Fuel guage won't drop below 1/2

Yes, the gauge goes to E with the key off. I am starting to think that the arm on the sending unit may be catching on the shallow end of the tank. I'll pull it and find out. Do I need to worry about sparks while unscrewing the sending unit, the gas tank is metal....?
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,468
Re: Fuel guage won't drop below 1/2

Do I need to worry about sparks while unscrewing the sending unit, the gas tank is metal....?

No, not really, But, safe practices dictates you should disconnect the Battery before attemping any electrical work Anyways....
 

jwiebe

Cadet
Joined
Jan 6, 2011
Messages
6
Re: Fuel guage won't drop below 1/2

Thanks for your help guys. She's fixed.
 

LippCJ7

Vice Admiral
Joined
Sep 20, 2010
Messages
5,431
Re: Fuel guage won't drop below 1/2

It would help others here to explain what you found also those who find this thread in the future using the search function can look for possible solutions in their situation, so please let us know.

Welcome to iboats!
 

jwiebe

Cadet
Joined
Jan 6, 2011
Messages
6
Re: Fuel guage won't drop below 1/2

O.K., well it looked like the fuel sensor had been turned around when it was previously removed (or replaced) and that the arm and floater were catching on the side of the tank. As a result, the float was not dropping down any further than 1/2 as gas was being used. Hope this is helpful.
 
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