fuel tank sending unit bad?

[Old No 7]

While out on the Water yesterday, I ran out of gas. My gauge says i have over 1/2 tank but when i shined a flashlight on what I can see of the tank, i didn't see anything. I knocked on the tank too and it sounded very hollow. the fuel bulb keeps losing it's prime. the motor runs a few minutes, bogs down and dies. I'm really happy i have a towing service!

The boat is a 1988 17' Sunbird with a built in 21 gallon plastic tank. I have at most about 2 inches of clearance above the tank. I'm guessing at this point but from everything else I've done on this boat. it is probably original.

How do i test the sender to see if it works? I've never seen one, and have no idea how they work.

Can they be fixed, or do you just replace them?

lastly, if it is bad, i imagine there dfferent types/models/brands i need to watch?

I was a bit too frustrated to look at it yesterday, but I'm going back to the boat tomorrow afternoon to see if i can figure out what the problem is. I would stick the tank, but the fill line has some severe bends in it. i'd never get anything down it.

Thanks for your help!

 

[Chris1956]

Re: fuel tank sending unit bad?

7 - You will need to gain access to the top of the tank. You should see a round plate with two connections, and about six SS screws around the perimeter. If you remove the two wires and the six screws, you can pull the sender unit out of the tank. It should have a float on the end of an arm. If you reconnect the wires, your guage should move as you move the float up and down. If not, either the guage, sender or wiring between them is defective. You may test the sender with an Ohm meter . As the float moves up and down, the resistance should change. I think the correct range is 30-240 ohms. When you figure out what is broken, replacements tend to be universal, and a new guage will work with the original sender, and vise- versa.

 

[Old No 7]

Re: fuel tank sending unit bad?

OK got it.

Thanks! I really appreciate it!

 

[kenmyfam]

Re: fuel tank sending unit bad?

Had a similar situation many years ago and the float was sticking part way down so it showed just under half a tank constantly as it ran further down. Seems like your fuel economy is great until you run out !
Now I fill up as soon as it shows half a tank.