fuel gauge

[unclebub]

My fuel gauge likes to bounce from empty to 3/4 full. When it is stable it usually reads wrong. Does it sound like bad wiring or a faulty sending unit? Thanks.

 

[Don S]

Re: fuel gauge

Sounds like a normal marine fuel gauge to me.
They pretty much tell you when you are full (gauge doesn't bounce) and that you have some unknown quantity of gas in the tank (gauge bounces).
Tank design, sender location, size of tank, baffles, all has an affect on the accuracy.

 

[Silvertip]

Re: fuel gauge

The fuel sender in the tank is a simple float on the end of an arm. As fuel sloshes around the arm bounces up and down and the gauge reacts accordingly. The more the boat bounces the more the float bounces and the more the gauge bounces. Take your fuel reading at the dock. Whenever the boat is stopped, take your readings then. The gauge reading under way is simply and exercise in watching the needle bounce around in a meaningless fashion.

 

[unclebub]

Re: fuel gauge

The fuel sender in the tank is a simple float on the end of an arm. As fuel sloshes around the arm bounces up and down and the gauge reacts accordingly. The more the boat bounces the more the float bounces and the more the gauge bounces. Take your fuel reading at the dock. Whenever the boat is stopped, take your readings then. The gauge reading under way is simply and exercise in watching the needle bounce around in a meaningless fashion.

Thanks Silver but there's more to it than that. There are times even in rough weather the gauge acts correctly. Othe rtimes it doesn't bounce but reads incorrectly.

 

[Silvertip]

Re: fuel gauge

There are three issues with fuel gauge systems. 1) the gauge itself (rarely the issue). 2) The fuel sender in the tank (it usually either works or it doesn't) 3) wiring between the sender and the gauge (pink wire). wiring at the sender or wiring at the gauge.

 

[Scott Danforth]

Re: fuel gauge

most fuel gauges are only an approximate indication. as Silvertip mentioned, is a simple float on the end of an arm attached to a potentiometer. since the boat changes angles (bow up, bow down, pitch starboard, pitch port, etc.) As Don mentioned, the best you get is full and something less than full.

there is technology that will read accurate fuel levels. they must be programmed to the tank shape. they are really expensive compared to the standard gauge. Since no one wants to pay for them, there is no benefit for the OEM's to use them.