The Rubber o-ring swelling is due to ethanol in the gas..any ethanol content = swelling.

But all carbs are touchy, seeing as an engine will only operate correctly at or very near the stoichiometric air/fuel ratio of 14.7:1. And given that ethanol content throws off that ratio (requires more liquid fuel), and given that most carbs today are fixed jet...it makes things more difficult.

The needle and seat is pretty much the most simple part of a carb, and it either works or it doesnt.

If the float has a pin-hole or leak..even something miniscule, it will make it not work. a spec of debris between the needle and carb body, will make it not work. Any flaw on the rubber seat, even a tool mark from installation...will make it leak.

But when its all put together right, and clean...the carbs work under the same principle as all other carbs...low air pressure that drafts fuel up the emulsion tube and into the venturi and air stream...

and "they" want to up it to 15%. i sure hope it gets shot down! 70% of our work is fuel related, 20% is actually mechanical and/or maintenance, and the other 10% is from the owners stupidity. Granted 15% would surely increase our business, but I DON'T want to see that because it will come at the cost of the customer due to invalidated warranties and the fact they have no other fueling options, other than Tru-Fuel, which is cost prohibitive in most cases.....

...never thought about it until now, but the 14.7:1 ratio is at sea level. We are at 1400-1500 ft. I wonder if that contributes THAT much to our "success" rate with non-adjustable carbs? (not in the repair end, but getting them to run properly)

Well I rebuilt many carbs lately and only had problems with the ones on a Tecuseh engine.(3 of them to be exact.) Had to tear them ones apart several times,,,2 of them finally got correct ,,the other was a loss. And yep,,I think I bought every bowl gasket my parts dealer had in stock.

I was starting to think these things were junk,,but maybe,,,just a isolated problem at my place. And I am having very bad luck with the odds.

If you can see my point,,,it makes me a little skittish when I see a Tecuseh. Considering 4-5 other carbs,,I had no problem with.

No fear,,,maybe the next will go smooth.

The o-rings that go on the emulsion tube are standard 1/8 x 1/4 so those you can get in Viton. But the bowl ring is more of a square ring, and I doubt you can find those except in Tecumseh or aftermarket numbers.

littletoes said:

Why not buy O rings that will not swell when exposed to ethanol???

Viton O Rings should work great, and you'd never have another problem with 0-rings again.

I need various types of 0-rings when working on different types of pumps...


http://www.marcorubber.com/material_chart.htm

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What do you mean??? I was getting the impression that they are no different than any other. Your the first to somewhat agree with me.

I have not run across one yet that I didn't have to tear back apart,,,at least 2 times.

Tractor-Holic said:

Tecumseh Carbs = Satans Masterpeice!..


--Nothing will mess with your head more than a Tecumseh carb,except maybe a woman...out of hundreds I have had,I think 50 worked "good"...some just cant be fixed ,I have concluded...especially after they sat with old gas in them "forever"...

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I weeks ago I was in the city where they made the engines . Can't remember the name of it. Me and my girlfriend had lunch, at a little diner ,right in town.

I seen the place where the factory's used to be. A local started pointing and explaining how it used to be.

Oh,,ya ,,I remember the name of the city now!! It was Tecumseh, Michigan. LMAO

Southern part of lower Michigan.

RED: You can have them. lol

When I order the next carb kit for one. I will skip the hassle of going back later,,,and order new float,pin,,extra needle and seat,,,3 bowl gaskets and new adjustment needles. If I do that,,I might not need to go back to the parts dealer for more parts.