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PSA: Don't mock up a tank unless you plan to put gas in it soon

walkerhoundvm

walkerhoundvm

Just trying to stay upright
Lifetime Member
City
Cave Creek
State
AZ
My build is right on the verge of being done, and one of the things holding it up was a zeroed out gas gauge. I was really racking my brains trying to work with the build shop to figure out what was going on. The gauges had been acting up, but even after sorting them out the gas gauge was still reading empty. I had spent an entire weekend earlier this year cleaning the tank, painting it, and checking the resistance of MTS sending unit before installing it...and then double checking it again after it was installed, so there's no way it could be the sender, right?

Well folks, PSA - don't mock a tank up unless you expect to have gas in it soon. This is what your sender will look like after ~10mos, even in the dry southwest with the tank able to vent. The brass float I used to replace the plastic one had deteriorated, even, it was full of gas. The whole thing looks nearly as bad as the 30y/o one I replaced with this one. Maybe this should be in the "relics" thread?

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Holy cow... That looks like it was sitting in salt water for 10 months.
 
Looks a lot like the one I pulled from my tank. Only difference is my tank was near full. I think it has a lot to do with the new gas blends.
 
I joked with the builder that I must've used sea water to clean the tank. It had a good week to dry out before I had a chance to install the sender, too.

@ag4ever - only issue is this one had never seen gas even. The gas was from starting it up. Pure dry build, but obviously not dry enough.
 
You gotta lay off that new algee blend I've been seeing the FAA is experimenting with for airplane jet engines !
 
This was an MTS sender, which as far as I knew had the better reputation of the aftermarket senders. May just be a Crown rebrand, I don't know? There's more rebranding in this market than I was aware of.
 
I had to look back on my red Scrambler rebuild thread, but I mocked/assembled my tank in December, first put gas in it in April, so four months down here in the "humid" zone, no problems :shrug: At the time, it was a 15 gallon steel tank, probably a Crown/Omix sender. When I pulled the 15 gallon tank out to replace it with a 20, it still looked new. BUT, it had been in "service".

I wonder if they cleaned your tank out with some type of powerful solvent (MEK/Acetone), and the residual fumes did that :shrug:

When I wanted to "upgrade" to a factory plastic 20 gallon tank, I found one within an hour from my house. It was in an 85/86 CJ-7 that went underwater in Hurricane Katrina. The sender looked like yours :huh:

I'll see if I can find a picture.

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Yikes! My 77 cj7 build I had an oem 15 gallon tank that was sitting around for 12-16 months empty but brand new. I did not have the problem you had but.... When I hooked everything up and got the motor running the engine was not running right and starving for fuel. I only figured that out after running a clear glass filter after the fuel pump. I replaced the mechanical fuel pump and even hooked up a temporary electric pump. Still starving for fuel. The only thing that was left was the sending unit. The fuel lines were all new and not collapsed, pinched, leaking, and they were the correct size. The sending unit was brand new no rust. I had pulled it out a few times and visually inspected it. Before I replaced the sending unit that looked great I tried blowing air through it. I could not blow air through the feed/ pick up line... I ran a small wire through the pickup line... found a small hornets or wasp nest in the line. While the tank was sitting on the garage floor waiting to be install with no lines attached, mother nature decided to intervene in my build! I had no Ideal and had countless hours wrapping my little pee brain around it. Ran great after.

There were no signs of debris in the filter and I did not put a pressure gauge on the line to see if the pump was working correct (PSI). Visually the fuel was coming out good when disconnected from the carb into a milk jug. As cheap as the fuel pump was I just returned and replaced. Thanks Mother Nature! Thanks!
 
spankrjs said:
I wonder if they cleaned your tank out with some type of powerful solvent (MEK/Acetone), and the residual fumes did that :shrug:
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I essentially just rinsed it out thoroughly with water, drained it and let it sit in the sun for the week with the ports up while waiting for the sender and check valves to arrive in the mail :shrug: Installed sender, checked the ohms, turned it upside down, checked the ohms, then screwed the cap on with a dab of RTV to keep it sealed.
 
I wonder if the brass float on the galvanized wire is causing some of this?

My float was like paper and fell apart in a small rain after removing it from the tank.
 
walkerhoundvm said:
I essentially just rinsed it out thoroughly with water, drained it and let it sit in the sun for the week with the ports up while waiting for the sender and check valves to arrive in the mail :shrug: Installed sender, checked the ohms, turned it upside down, checked the ohms, then screwed the cap on with a dab of RTV to keep it sealed.
Click to expand...

That is really strange. As dry as it is where you are at, you would think that all of the water would have evaporated/drained within a few hours. I wonder if that particular, or batch, of replacement sending unit was not plated correctly :shrug:

When I installed a 20 gallon tank, I was lucky enough to find/purchase a NOS sending unit. It still looked brand new, and it was close to 25 years old. After 40,000 miles, still works great, too. Cheap a$$ replacement parts :banghead:
 
ag4ever said:
I wonder if the brass float on the galvanized wire is causing some of this?

My float was like paper and fell apart in a small rain after removing it from the tank.
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Interesting thought. I know nothing about the arts of metalurgy, but I'll consider it a potential cause. The brass one was recommended because the plastic ones are said to fail. So much for that. The sender is MTS branded.
 
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