Drifting floats

[refit1701]

Hi everyone, long time no see.

I have been rebuilding my ETW1 and researching the quirks and secret settings of the carb. I have several carbs, at least two of which appear to have been rebuilt by the Army in the seventies and never opened since then. I opened them up to take a look at the differences in the old parts and the new kits you get today.

Once thing I noticed in every example is ridiculously high float settings. With the top cover off, they would be high enough to rest against the top, not 5/64th like is specified.

Do these floats change their setting over time from the bending of the tab or is there some unwritten rule to set them at max right out of the gate.

My engine stumbles when you push the pedal down and only behaves somewhat better with partial choke. I have checked it for air leaks and it doesn't seem to have any. The movement of the pump is fine.

[Cal_Gary]

Wow John, welcome back! We've missed you-hope all is well!
My float has to be precisely 5/64th-anything more or less results in a flooding situation, or starving situation.
My old carb did what you're describing-having to apply some choke to smooth out the engine. In my case there was a slight air leak at the base gasket allowing too much air into the mixture. Replacing the carb and gasket solved both issues.
Don't be a stranger!
Gary

[NAM VET]

in my case, recently my float was incorrect, mostly because I had removed and replaced the needle valve and seat several times, when my problem was actually a failing fuel pump. So bought one of the OEM gasket kits from a vendor, cheap, and took off the top of my carb. First removing the long idle needle jet, the brass one on the top of the carb. Precisely set my float, per my recent pictures on a thread here, and then my idle needle worked fine at about a turn out, and my engine stars and runs fine. I too wonder how carb bowls can be so off with a tune, and all I can think is that someone put in a different needle and seat. I use the one with triangular viton tipped needle. Perhaps these precise matched parts were swapped out for non-matching parts or something. Can happen. I actually put my needle in backwards at first, and had to do it again. If I can make such a mistake, anybody can. A month ago, I posted pictures of my own saga with my float level. And welcome back.... hal

[refit1701]

I ordered a Carter float height gauge which should be here soon. I noticed in the fine print of the carb sheet that if you have the three piece needle (needle, pin and spring), you should put a 050 feeler gauge between the tab and needle when setting the float. All the carb kits I have come with the three piece needle.

I am currently doing some repairs to the truck. The gasket between the intake and exhaust manifolds blew out last summer and the valves needed adjusting again. The "pcv" valve has never been hooked up since I discovered the passage into the intake was block by carbon, essentially I have been running road draft. The exhaust flap valve was broken before I finished the first restoration and we are about to replace that too.

The bypass oil filter housing is the wrong one without a drain plug, it's getting replaced too.

General cleaning and degreasing and some engine paint and it'll be back on the road in a few weeks.

I intend to flush out the differentials and adjust the brakes. Fun, fun.

[NAM VET]

I have "heard" that the spring/needle and seat are old. I suggest the less complex simple viton triangular needle and seat, available from the vendors. Charles Talbert has an upgraded set which allows more fuel in high demand, but the float level is different. His advice is to set it correctly with the float level, and leave it alone. The newer seats rely on the float, properly set, to precisely meter the carb's fueling needs. This assumes a fuel pump pressure somewhere between about 3 pounds to a max of 5 psi or so. Any more pressure can overwhelm the system and flood the engine. hal

[refit1701]

I'll look through my stuff and see if I have the one piece needle. My fuel pump is stock so the pressure should be OK.

Come to think of it, it's been ten years since I overhauled the pump, maybe I'll do that now too. It's much easier to get to at this point.

[Cal_Gary]

Hey John,
I thought you'd sold your truck. Did you end up keeping it?
Gary

[refit1701]

Hey John,
I thought you'd sold your truck. Did you end up keeping it?
Gary

Good Heavens, no.

2019 BSS M37.jpg (206.61 KiB) Viewed 460 times

[Cal_Gary]

Excellent!
Gary