Do Cork Floats "go Bad"?

64 cj5 with an original cork style fuel tank float. I've noticed more and more cork "looking" debris at the bottom of the fuel tank lately and the sender itself tends to err on the side of empty more than I remember.

There is usually some sort of crap in my tank when I rinse it out but this seems new.

Do floats soak and go bad after years of use? With the new ethanol fuels and additives I've been using to combat them (stabil, seafoam, etc), The cork is exposed to alot more than just fuel in recent years.

Follow up question: If I were to replace the float with a brass one, Could I just replace the float or does the whole sender need swapped?

 

I don’t think cork likes ethanol gas. Same with old age. Cork deteriorates over time. Other sending units used brass floats or plastic floats. Most floats “clip” onto the wire arm, though I have seen brass floats soldered to the arm.
You could probably keep your sender and just replace the float, if you have a spare float.
-Donny

 

Does your float arm go through the float or wrap around? I can 3d print a float for the through wire. the float with the wire wrapped around have replacements available.

Send ma a pm if you need one printed out of plastic. I'll have check how mine is doing after 2 years and make adjustments.

 

The cork used to be coated with shellac, I believe. But shellac is alcohol-base, and hey, guess what ethanol is?

 

When I first rebuilt my 2a the cork seal for the sender disintegrated and kept clogging the line. I had to stop all the time and take line off the pump to blow it back out. I dont recall if the float survived

 

I remember reading on a small engine forum about how ethanol very quickly destroys the cork floats some carbs used to use.

Is this compatible with your sender arm? This is what I used on my Jeep, but I was just replacing another plastic one that had failed
Omix-Ada | 17729.01 | Fuel Pump Module | OE Reference: 5357373-F | Fits 1955-1986 Jeep CJ https://a.co/d/4fcXvKo

 

That's the same one I used in my Corvair after 2 brass repops split and failed after less than a year
We'll see this spring if it still swims or sinks....
Was a direct fit, clipped right into the GM arm.

 

I looked through my old photos but it seems like I didnt get a shot of the sender the last time out was out of the tank. Ill pull it out this week sometime to get an answer on this So cool you can print em!

That explains everything haha.

 

Here's what my printed float looks like, this one is about double in size from the original, with the arm adjusted as needed. I didn't know how it would hold up or how the buoyancy would compare since internally it has a honeycomb.

I'll see about adjusting the file in the next few days. It's been in service 3 years now.

20210121_094253 by Joe with a jeep, on Flickr

 

So after about an hour drive today there was a TON of brown sediment in my freshly changed fuel filter bowl. Shined a flashlight down into the tank and noticible chunks of cork were present. Shook the jeep slightly to move the fuel around and watched the cork on the float arm dancing around wildly like a dashboard hula dancer. Looks like the center channel where the wire arm goes through the middle of the cork has eroded. The edges of the float also look like theyre dissolving away.

Rather than waiting for a replacement float to be printed (Thank you Jw60 for the offer), I just ordered a new unit with a plastic float from QT Military. Looks like I have another weekend of cleaning the tank, pump, and carb out again once it arrives .

Not sure what was more at fault... Ethanol content in the gas or my use of seafoam/Marvel mystery oil. Either way, Hopefully the new float will last a while. Fingers crossed.