MTFCA Forum

The other day I replaced the carburetor on a T with a rebuilt carb done by a dear deceased friend about 10 years ago. But gasoline wouldn’t stop pouring out of the inboard hole next to the choke shaft hole. I tapped and tapped hoping for just a stuck needle in the seat - to no avail. So I drained the carb and removed the Bowl recognizing a new float, needle and seat. Next I placed the float in a cup of water and it sunk. I don’t feel confident applying solder thinking it would make the float too heavy. Is there any other product that would fix the leak between the brass float seams but not make the new float too heavy - and not negatively react to gasoline ?

Save yourself a bunch of frustration and just replace it. https://www.modeltford.com/item/6201.aspx

Thanks John but I’d just be replacing a 10 year old never used new Lang’s float with another one. Suppose I could call and ask for a float test before sending but, in the tradition of restoring, was just wondering if there was a lightweight ‘brush on’ or ‘spray on’ product someone has used successfully. Don’t think Flex Seal is gasoline proof

George

you stated that the leak was at the seam, but haven't mentioned any testing method to prove that. So, I'll go with the seam being the issue...you'll need to get the float completely dry inside. Prick a hole in the float near the hinge, on the underside and allow the float to warm in the sun for several days, shaking it periodically until all sound of liquid is gone. Flux the seam and with a large iron, simply reflow the solder that is there...do not add any. Flux the hole and just dab a bit of solder onto it and if the brass is clean and the flux is RMA flux and you use eutectic solder, that tiny hole will be sealed in an instant with no discernable additional weight, and if a little weight IS added, the hinge is supporting it and it will not materially reduce bouyancy.

Great idea Scott ! In my initial post I said “Next I placed the float in a cup of water and it sunk” (over time). I’ll go on the hunt now for RMA flux and eutectic solder. Thanks !

George, I did get that, but I don't think that condemns the solder joint. Next, I'd put it into very hot water and watch for either bubbles, or a shimmer of gasoline escaping...you may be surprised to find a corrosion spot, pinhole in a dent, or something else which is really the culprit.

Anyway, eutectic 63/37 solder is key to this repair. Not some crappy 60/40 junk nor non-lead plumbing solder at the hardware stores. Either of those will lead to a giant mess and possibly a larger leak. If you can't find elsewhere, MSCDIRECT carries it...Kester brand.

After drying the gas out the float, place in warm water and hold down, bring the water up to just to just before simmer and look for bubbles coming out of the float. Mark the leaks. You will need to drill a small vent hole, because if you don't the heat will increase the internal pressure and can just keep blowing out the place you are trying to fix. If you look at some brass floats you will see a spot of solder, thats what it is, vent hole. Keep the solder to a minimum, even a little bit can change things. You may have to redo a couple of times.
I am thinking, that if it is taking on liquid that fast, might be a lost cause and better of with a new one.

One thing to add about soldering float. After you fix leak , let float cool down before you close the vent hole. If float is still hot you can cause float to have a vacuum inside, may want to collapse. Dan

Thanks Dan. Good consideration. I’m going to try Scott’s method on my repop carb but, in the meantime, I went out to the barn and picked out several original NH floats and put them all to the test. Picked a winner, installed it, turned on the gas and didn’t leak - car running or not. Went for a drive. Of course I turned the gas off until next drive.

I should say this NH is only a temporary replacement while I wait on the U&J’s
Return from Helena MT

I suggest you just get some modern float plalstic , make a float and be done with it!

This is from Langs, I assume most vendors have it.



TH

George, most of those floats from ten years or so were being made in India and were some hard brass colored metal that would not hold solder. They leaked and didn't float very well to begin with.

I don't know where they are coming from now and I haven't bought many since I don't fool with NHs but they have to be better.

Combined with the needle and seat sets made and sold as the "correct original style" that had the tips cut on a form cutter instead of being ground so they were actually round and would seal in the seat, it about took some guys out of the carb rebuild business.

I don't know where they had the needle and seat sets made but I still have some in the packaging they were sold in that were so rough I could see the cutter marks without a lens.
At that time I was still doing NH's and I tried to regrind some. They were made from such cheap crap metal I couldn't grind the tip surface on my needle making setup and ended up making new ones from piano wire, hardening them and grinding the tips or regrinding the old tips.

Not that it has much to do with this but the only good needle and seat set I have seen for NHs come from Scott Conger.
Full flow, viton tip and they fit right and work.

I can make needles for about anything but I am always so backed up I would buy sets if they were available in good quality for other carbs

RE your U and J's. I make the entire set for those, seat, needle, whole thing.

Good idea Terry.... I hope that’s the plastic float material that Stan will be using on my two
U& Js..