Fuel Sender - Bob don't bob

knattrass · Post by **knattrass** » Wed Oct 08, 2008 3:36 pm

So we finally got around to pulling the new sender out of the tank because it was only bouncing around a 1/4 tank. We lifted the arm and the gauge moved towards full as it should. So we pulled it out and the brass bobber had no fluid in it. So we decided to dip it into a bowl of gas and it didn't float. It appears that it doesn't have enough float to overcome its weight. The brass looks to be soldered correctly. Is there a replacement?

m-37Bruce · Post by **m-37Bruce** » Wed Oct 08, 2008 4:13 pm

Both of mine are cork?

GregL · Post by **GregL** » Wed Oct 08, 2008 7:52 pm

Strange that it doesn't appear to have fluid in it, but it won't take much.

I had (have) a cracked float and tried to find just the float to no avail. In the meantime, before I can solder repair my float, I've got a champagne cork in it's place and it works great. It hasn't been very long so I don't know how it will do over time.

FYI, don't try to epoxy the float, the gas will eat the epoxy away.

vtdeucedriver · Post by **vtdeucedriver** » Thu Oct 30, 2008 11:41 am

Some fuel sending units in aircraft in the 40's were cork that were sealed with a wood varnish, I think. That seals them up pretty well. But let me check if it was actually wood varnish

Lifer · Post by **Lifer** » Thu Oct 30, 2008 3:58 pm

Someone else had that problem recently, and I suggested using a cork bobber. He replaced the brass float with a champaign cork and his fuel guage has been working just fine ever since.

k8icu · Post by **k8icu** » Thu Oct 30, 2008 6:31 pm

knattrass wrote: So we pulled it out and the brass bobber had no fluid in it.

Why would you want fluid in it? I would think you would want it to be like a steel drum on a dock...you want it to float on top of the fuel. Check to see if it is cracked or has a pin hole. Sounds like it is sinking.

A wood dowl will work as well as cork.

knattrass · Post by **knattrass** » Fri Oct 31, 2008 4:37 am

We pulled the bobber, sanded it back to shiny brass, and held it under gas for 20 mins. No leaks. What we found was the the little coat hanger wire arm on the sender fit into the groove on the bob. However, there are 2 grooves offset so you can install bob directly under the sender or bob can be installed offset from under the sender. We found that the offset position added a little extra torque to the arm and made it work??? Go figure, the tank plumbs 3/4 full - right on the money.

Fuel Sender - Bob don't bob

Fuel Sender - Bob don't bob

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Re: Fuel Sender - Bob don't bob