85 K10 Fuel tank question

[BackCountry]

When I bought my k10 it only had the reserve tank in it and it needs to be replaced. The problem is that it seems to be a 12.5 gallon tank and all I seem to be able to find are 16 or 20 gallon tanks. I don't want to install the main tank because I've already bough a new sending unit for the reserve tank and can't afford to buy a new sending unit AND a fuel tank if I buy the main tank.

Does anyone have any more info on the reserve fuel tank sizes?
Thanks in advance.

[LTZ C20]

12.5? That's very odd. Gas tanks were either 16 or 20, I've never heard of a 12.5. Something doesn't sound right here.

[BackCountry]

Agreed, but I've filled it up from empty several times and that's what it holds, so I'm not sure what to do. It needs to be replaced and soon.

[LTZ C20]

When it's empty, how do you know it's empty? For example, because the gage is on E or because you run out of gas and the engine starves for fuel? You should post some pictures of your fuel tank.

[BackCountry]

I know it's empty because of where the gauge is at. I've run it out of fuel before. My gauge is weird: although the gauge is set left and right, my needle moves up and down so it's empty when the needle points to the A in the word Unleaded at the bottom of the gauge where it says unleaded fuel only. I'll try to get a pic of the tank in a little while when my son gets home.

[Captain Swampy]

My guess is you have the 16 gallon tank. Your pick up assembly isn't getting all of the fuel out. Maybe bent or something. The sending unit you bought is probably for a 16 gallon tank. Maybe check the part number? I never payed attention if the 16 and 20 use the same pickup or have different ones.