Fuel Guage Not Working

[mark_53]

Anyone have experience with how the fuel gauge fails vs. how the sending unit fails?  My fuel gauge suddenly pegged empty.

[Ron Hill]

Mark : I'll guess that your original sending unit finally failed!!  You can check your wiring and make sure all is connected.  Look in the Mainsheet tech notes for an article on How to replace the Fuel sending unit. 

Also many posts on that topic here on this form!!

A few thoughts

[KWKloeber]

Disconnect the pink wire from the gauge S terminal and test the gauge. The Teleflex gauge troubleshooting instructions are on the tech wiki - "Engine" > "Electrical"
https://c34.org/wiki/index.php?title=Catalina_34

Once you determine whether the gauge is good, reconnect the pink wire and disconnect it from the sender and repeat the same test. That will tell you whether the circuit is good.

Lastly you can measure the resistance to ground at the sender terminal for the pink wire. The values are APPROX 33ohm full and 240 empty.

[mark_53]

Mark : I'll guess that your original sending unit finally failed!!  You can check your wiring and make sure all is connected.  Look in the Mainsheet tech notes for an article on How to replace the Fuel sending unit. 

Also many posts on that topic here on this form!!

A few thoughts

Ron you sound convinced it's the sending unit. Is that because of the failure mode or probability?

[Ron Hill]

Mark : After 31 years - the probability is that if the connecting wiring is intact - that the wiring/contacts inside the float gage are most likely worn out!!

My thought

[Noah]

If all wires are tight, I vote for the float sender inside the tank. I replaced mine with a new off the shelf float sender, that worked fine. Unfortunately, six months later my tank started leaking (unrelated except for age) so I ended up with a new tank that came with new vertical-style sender installed (not a swing arm float). Sorry I tossed the first replacement sender, or I would send it to you. They are about $29 at West Marine.