Fuel Sending (sensor) unit

[convincor]

Boat: 1988 300 Weekender

My fuel sending unit (port side)has been jacking around on me lately. It always reads either empty or half full when the tank is full. I have checked the gauge and it is correct. I pulled the sending unit completly out and the float floats in water just fine. When I move the sensor arm up and down (while out of the tank) the gauge moves and looks correct. My guess is the float is bad. But the confusing part is that it floats in water just fine. Is there a difference?

Can I buy just the cork float or do I have to buy the whole unit and where is a good place to get it?

Convincor

 

[tdappleman]

You may not want to replace with cork - the newer gas formulations can break down the coating on them and then they break the cork itself down. Maybe someone will know where to obtain just the float piece. I replaced one in a different boat last year and the sending unit with float was about $40 at Napa. The float it came with was some type of black plastic.

 

[Quint4]

gas is lighter in weight than water....this may account for it. I replaced my sending unit recently and fixed my inoperative fuel gauge....I say replace it while it's out and see what you get.

 

[convincor]

Thanks for the information. So, are you saying that I can get the sensor at Napa? The cork seems good and solid, but you are right, it might not be acting correctally with the fuel. And without seeing inside the tank I cannot tell for sure.

 

[tdappleman]

You can get it at some Napa stores. My local store has a dedicated marine section and has quite a few parts. This one is available at West Marine and is the same unit as mine except for the same price it came with a gauge which I didn't need.

 

[Crushin It]

Travis,

What size tank or how many gals is your tank. I am having the same issues...

 

[convincor]

It is a 101 gallon tank. I will check my local Napa. I love West Marine, but I hate paying for something double the price because it says marine too.

 

[Crushin It]

Was it an adjustable length sensor or fixed length????

 

[tdappleman]

Villian - the issue I had was on my other boat - a 2001 Parker which had developed a leak in the original 110 gallon aluminum tank. When I replaced the tank I put a new sending unit in since it was all apart anyway. The one I obtained from Napa was adjustable - but I was able to use the original length and then bend it slightly for it to have the full range of motion. If you are having similar issues - the part is cheap and if you can easily get to the part it's a cake walk to replace. Make sure you use the ground wire already part of the boat - it will attach to one of the 5 or 6 mounting screws on the sending unit. Then the sending unit itself will have a single lug on top to attach the gauge wire to. Test the motion of the unit before final install - I did this by measuring my tank height inside. Then you can bend/adjust as necessary so you get accurate readings at full/empty.