Alternate methods of repairing a card float

Question:

While reading the November Mechanic on Duty section, one of your comments jumped out at me. You said to never solder a carburetor float after it has been determined that it has taken on gasoline. I agree with your advice, considering the chance that the float might explode upon re-soldering. But, you gave no options for repair.

I recently repaired a carb float using other means.

What I am going to suggest is for the determined and desperate mechanic. It has worked for me on my tractor carburetor float. Last fall, after a few years of false diagnoses of a flooding 1979 John Deere tractor carburetor, I found that the carb float had a small amount of gas inside it and this issue was causing the float to flood the carb, but only on hillsides.

I could not get a spare carb float since the parts houses were closed and I needed to complete the tractor work on that weekend, so I determined to try the following:

I placed the brass float in a pan and warmed it over a stove in my shop to cause the gas to leave the float. The float had a small amount of gas in it and it quickly boiled off (out) of the float. Placing it in the sunshine would have provided the same remedy.

I then followed the instructions for POR-15 (always on my shelf) and cleaned the float thoroughly and applied two thin and separate coats over the float body. In theory this should seal the float. My only concern was that the two POR-15 coatings would be too heavy for the float to work properly. After a full cure overnight, I reinstalled the float into the carburetor and have been using it regularly. There’s been no more flooding out on hillsides. I would not recommend this for automobile carb floats unless you are desperate.

Answer:

That’s a super solution to the problem, Sam. My only reservation about advising readers to try it would be that Idon’t know how gasoline and alcohol affect POR-15 over time, and I don’t know of any tests that have been conducted to determine what, if anything, will happen. It may very well be just fine, or it could flake off or dissolve and stop up a jet, but in your case, time will tell.

I didn't offer a solution other than replacing the float because I don’t know of one that wouldn't be dangerous. As you surmised, leaky metal floats become permeated with fuel and as a result become potential fire crackers, even if empty, once you beat them up to solder them.

I have seen gas tanks repaired using car exhaust pumped into the tank to deprive it of oxygen, but Iwouldn't try it myself, nor would I recommend that trick to anyone else. However, a carburetor float is so small—and assuming there is only one hole—I know of no way to replace the air inside it with an inert gas.

If another float cannot be found, your POR-15 solution sounds like it is well worth a try, though as you are aware, you could have to clean the residue of the stuff out of your carb at some point.

Incidentally, epoxy might just work too. Thanks for the tip.