copper vs plastic carb float

copper vs plastic carb float

elwood blues

Always Off-Roading Jeeper
Export, PA
1978 CJ7 4.2L Comp Cam & valve train, MC2100 carb, MSD ignition, Dana 30 front, T18 trans, Dana 20 txfr, AMC 20 rear.
What are the differences (other than the obvious) between a copper and a plastic float? Are there advantages and disadvantages to one or the other?

Floats can be made of different materials, such as sheet br<-BAD WORD-> soldered into a hollow shape, or of plastic; brass floats can spring small leaks and plastic floats can eventually become porous and lose their flotation; in either case the float will fail to float, fuel level will be too high, and the engine will not run well unless the float is replaced.:mad:
I am getting ready to do a rebuild on my carb. Should I just go ahead and order a float as well? Is it good practice do go ahead and replace it any time you do a rebuild?

I am getting ready to do a rebuild on my carb. Should I just go ahead and order a float as well? Is it good practice do go ahead and replace it any time you do a rebuild?


Just buy a good quality FULL rebuild kit, and the float will be included with it. It is allways good practice to replace everything when you have something like a carb taken apart.
X-100000000 on full kit and rebuild unless you like rebuilding it more than once.
Does it really matter then which one you use?
What Carb are you rebuilding?
A M/C 2100 from a '72 Mercury Comet (it's a long story...)
Well, I just ordered the kit from Autozone "Gp-Sorensen / Carburetor Kit". I don't know if its a "FULL" kit. $39.99 I went ahead and ordered the float as well. If it has it in the kit, I will just return it. I will check that before I ever leave Autozone. Lord knows I will be making plenty of trips there in the future. :)
Copper (actually soldered brass) or plastic (I think it's called nytil)... Hmmm...

Both have advantages and disadvantages.

1) A brass float will keep the exact same float level forever until it springs a leak, then it will sink up to the hole or crack that has formed. This can cause your carb to completely become a fuel siphon atone inopportune moment!

2) Plastic works great and can never spring a leak as it's actually a high density fuel resistant foam. The BIG problem with these types of floats is that they loose buoyancy over time and can change your fuel level in the bowl as they 'sink'. You have a self detuning carburator.

What do I like? Brass, the float level stays exact for the life of the float and the failure rate is very low...

Happy carb rebuilding!!!!! :)
Thanks you guys, all of that was great info that I didn't know.
I use brass, but during a rebuild I check it.
Fill a bowl or cup with as hot a water as you can stand then submurge the float, if bubbles form it has a leak. The hot water will make the air inside the float expand and show the leaks.
Brock that's a clever way of checking one, will have to put it in the tech side of the brain (well OK also wrote it down too).

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