I have a couple fuel gauges that tend to bounce around a bit (small swings, not large ones) and it is a bit annoying to me. My first thought is I have a bad ground. My second thought is that the senders have likely never been replaced and are therefore 20 yrs old. This happens while both stationary and while moving along. My curiosity is also driven by what appears to be one engine consuming a noticable amount more fule than the other and I would like to know if this is really true.

I don’t know where these sender units are located on my 1996 32’ Active Thunder – anyone able to advise here? I kinda suspect they are under the bench seat. Under the bench seat I have sort of carpeted box mounted to the back wall (wall between bench and engine compartment). This box seems to be hinged on the top making me think it is intended to swing out for access, but it is not cut for this to work….seems strange to have this cutout for something and yet I have yet to find the easy way to get in this area. Anyways, I could peek in there a bit and it looked like either senders or battery switches were back there? I’ll need to throw a scope in there to investigate.

Once I find the senders the plan is to clean and scuff all connectors and throw some dielectric grease on all (this would include doing the same at the gauge and it’s ground). Depending on how things look at that point I may be looking to pull and replace the senders. If I need to replace the senders, are electric inductive units the way to go (vs. a more traditional float?)
http://www.livorsi.com/catalog/senders_auto.htm . If nothing else I guess this would eliminate a concern about livorsi gauges being a bit picky about senders. Any recommendations and guidance would be welcome.

Thanks!

- scott -

I pay ZERO attention to gas gauges on boats. Learn what GPH your boat typically burns and track by hours. Of course newer boats have Smartcraft, etc. and tell you within a few pints how much gas you have / burned.

You can order sending units with delay built into them, to minimize needle bounce

best bet is to understand usage and keep mental track of it, gas gauges are netorius for being a wrong. You could install a flow meter on what you got and keep track that way. All of my boats 1/4 was empty for me, and usually start looking for gas just after half.

Why would anyone expect reliable fuel gages in a boat ? Gee whiz, boats only cost a fortune already.

On mine, I have a door that opens on the floor under the back seat to get access to the sending units/fuel pick ups/fuel lines.

If its only the gas gauges that have the bounce, fill it up and keep running until it runs outta gas, then you know exactly on the gauge where it runs out...LOL

Old school. No electricity. No moving parts. Basically it measures the weight of the fluid on an air line. Probably been in the boat since built and still works.

The senders are under the bottom of the carpeted box. Fuel gauges always bounce when running in any kind of waves.