The Stovebolt Site Forums The Shop Area Engine Shop Rochester 2Jet float

I’ve been driving my 1965 C10 truck for approximately 800 miles with the same Rochester 2Jet mounted on an original cast iron two barrel manifold on a 283 SBC.
This weekend I had trouble getting the engine to run and idle. A look under the hood showed fuel spilled onto the manifold. I decided spark was good so I tore down the carburetor and found the float was partway filled with fuel. It must have a pinhole somewhere. My parts drawer had a spare float, but it did not look EXACTLY like the original. The float was the same but the arm was slightly different. I installed the float, and the truck is up and running just fine. Nothing seems wrong at all and no more fuel spillage onto the manifold.
I have no idea how old the float is that I just installed. So I ordered another float which arrived today. It looks identical to the one that is currently in the carburetor and working fine. I will assume that the float arm has different designs. The float is exactly the same shape and size. Here are some pictures. Should I have any concerns?

If it works, it works.

I recently had the same problem with an Autolite 1100.

Float was filled with fuel. It's also and "offshore" unit.

The new float, which was probably meant for the original American made carburetor, was similar in appearance but slightly different. So far it's working but was more difficult to adjust to fit the Chinese needle and seat.

The float with the longer depth adjustment tab is a later design with the float pin hole repositioned several thousandths to give additional buoyancy on the newer carbs.

Each float carries its own part number, and Rochester does NOT state the later superseded the earlier. They also do not say it doesn't. But part material lists for the carburetors using the earlier float printed AFTER the introduction of the later float still show the original part number.

Are there any issues? I do not know.

Jon

Lugnutz Might consider float drop,they would have you check that so if you ran it out of fuel the float wouldn't get locked down and cause it to flood over . This could happen thousands of miles later maybe out along the road. Easy test run it out of fuel at home.

Well, the old float definitely had fuel inside. It got so heavy that the needle wouldn’t close off the fuel from the fuel pump. Thus, the carb bowl was spilling out fuel. What you describe would look exactly the same. New float fixed it.

I had a '72 K10 that had the famous sinking phenolic carb float. It got saturated with gas and messed with the gas level in the bowl.

I bought a phenolic float and it’s in my spares drawer. Are they notorious for leaking?

They were back then anyway. When I mentioned my issue to a mechanic, he said "Oh, the famous sinking float" (or words to that effect.)

I prefer the brass floats- - - -yes, they leak on occasion, but the plastic ones get fuel saturated and don't exert enough pressure on the needle valve to overcome fuel pump pressure. Floats have two adjustments- - - -"float level" which sets the upper limit of fuel in the bowl, and "float drop" which keeps the float from bumping the bottom of the chamber under periods of high flow- - - -full throttle passing, etc. The new design float will probably need some attention to assure that the float drop setting is correct by bending the long tab. Both adjustments are important. A too-high upper limit will cause flooding, or possibly running rich due to the fuel level in the float bowl being too high in relation to the venturis.
Jerry

"I bought a phenolic float and it’s in my spares drawer. Are they notorious for leaking?"

I was told long ago that phenolic was Swahili for "leaky float". Cannot verify the source.

Jon

You might think I’m kidding, but I speak Swahili fluently. I spent 4 years in Kenya, East Africa.

The brass float in my carb developed a leak. I soldered it up and it's been good ever since. That was > 20 years ago. I wonder why it developed a leak in the first place?

"You might think I’m kidding, but I speak Swahili fluently. I spent 4 years in Kenya, East Africa."

So you can verify/deny the truth of that comment. I suspect the real source was some disgruntled mechanic that got tired of replacing them, and thought no one would argue with the Swahili comment

In any event, we never bothered trying to test one. If a brass float was available, we used it. If a brass float was not available, we would install a new phenolic float.

Jon.

Jon, here is one of my way backstories. My father was a Methodist minister and we were hosting a dinner at a church camp for Methodist missionaries, He had 2 sons my age. The 2 boys spoke 4 languages one was Swahili plus English French and I think German. During the dinner, the boys talked back and forth in Swahili which the rest of us could not understand. So I politely ask them to speak to us in English. Well, guess who got ostracized?? Yup! me. Their father had been imprisoned by the Mau Mau for about 6 months. Then the older boy became a missionary In Kenya and was also imprisoned sometime in the 70s I think.

Since my phenolic float is a spare, I think I’ll first weigh it, then submerge it in some gasoline for a month, then weigh it again to see if it absorbs fuel or leaks. I’ll post my results.

Nitaweka floti chini ya petrol kwa mwezi moja kuona kama floti ni nzuri au mbaya kabisa.
(I will submerge the float in gasoline for one month to see if it’s good or completely bad.)

Any links to purchase new brass floats?

Donf,

If you plug in "Rochester 2jet replacement brass float" into your web browser search, you will find at least 4-5 sellers offering the brass replacement floats with a variety of pricing.

Mine was $10.35 free delivery through eBay.

The NEW REPLACEMENT brass floats are made in China. If your fuel contains ANY ethanol, EXPECT THE FLOATS TO LEAK WITHIN 3 MONTHS! The solder used is NOT compatible with ethanol.

Would highly suggest either new old stock brass or visit a swap meet and buy a used carburetor and hope the float is good. Either is better than buying the new Chinese made brass floats. Even the phenolic is better than the Chinese made brass ones.

Jon