I have tested carburetor floats in hot water and looked for bubbles. Is there a better way to test for leaks?
I see people say they "pressure tested" a float. What should that mean?
How do you test them?
Tom, I don't know if this works or not but I have heard this done for brass floats. Warm the float but don't get it hot to where the solder plug will melt. Make a bath of really cold water and then quickly submerge the warm float into it. As the float cools, the pressure inside will lower and if there is a hole it will draw water in. Other than that I have no idea how to check them.
The only way I know to test them is to submerge them in hot water, and look for bubbles (like you say you already do) It works very well.
You could put it in a vacuum chamber. If it explodes/swells, it WAS good.
I only know of the hot water test for brass floats. There's no fitting on them to pressure test so that's out.
If you warm the float up and put it in a cold water bath, then water will be drawn into the float. How will you get that out?
Better to put them in hot water and look for bubbles.
Dave, yes you're right. At least you'll know that it has a leak :-)
To get the water out, you drill a small hole and drain it, then you can solder up the hole and retest in hot water.
On my M Farmall the carb had filled with water and frozen, collapsing the float. I unsoldered the two halves, reshaped them, then resoldered the halves and used it.
Brass floats can usually be repaired.
Submerge it in a solvent like lacquer thinner.
Tom, does your float feel like there is fuel inside it? I'm assuming that you have a brass float. If there is fuel in it, you may feel it slush around inside. Hold the float with a gloved hand and gently heat the float with a hair dryer or heat gun. Watch for steam. If you can do it on a cold day the steam will be easier to see. Then if you find a leak continue to gently heat the float until the steam is gone. Making sure you know where the hole is apply a little flux to that spot and then, heat with the heat gun the spot where the hole is and dab a little solder over the spot until it just flows. Be careful not to get the float to hot or you'll have more trouble. Once you fix the hole and the float cools, put the float in the water and watch for bubbles.