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Thread: Carburators..again.

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    Carburators..again.

    Rebuilt my SU H6 carbs. today with huge success. Most of the old cork came out as crumbs while some of it had completely vaporized.
    Put in new jets and needles, centered the needles and installed all new gaskets and seals.
    Car runs great, a huge improvement.
    Here is the problem. Everything is a little tight and the choke springs are not strong enough to pull the jets back up when I release the choke.
    I put 3 in 1 oil on everything as I assembled the carbs.

    Will this loosen up with time or is there a trick I don't know about.

    Thanks
    Steve

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    Great Pumpkin TR3driver's Avatar
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    Re: Carburators..again.

    You need to polish the surface of the jets. Any abrasive type polish will work, ISTR I used white toothpaste and my fingers last time. The shiny surface will slide through the glands much easier.

    If that doesn't solve it, I would replace the spring inside that spreads the jet glands. Sometimes, people stretch those springs in an attempt to get the glands to stop leaking. New return springs wouldn't hurt either. TRF sells just the springs for a reasonable price.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Great Pumpkin NutmegCT's Avatar
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    Re: Carburators..again.

    +1 on the polishing. I used fine steel wool, then toothpaste.

    I also discovered that one single spring (heresy!) was sufficient to pull the two jets back into position - so I removed the "extra" spring. Also made pulling the choke knob out much easier.

    Tom M.
    Mac & Phyllis Take a Trip: http://nutmegflyer.com/trip-details-daily-updates/
    History: 1976 MGB, 1959 Triumph TR3A, 1960 Mercedes-Benz 190b, 1958 Rambler American.
    Current: 1953 MG TD27318.

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    Re: Carburators..again.

    I replaced the springs. Is it ok to pull the jet out the bottom to polish it. It seems like when I put it back in it might damage the cork.
    Or should I pull out the entire assembly requiring re-centering etc.

    Thanks

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    Re: Carburators..again.

    It's a risk, with cork, IMO, but I have done it. Even without that, my experience has been that the cork doesn't last long and has to be replaced every few years. I like using O-rings much better, as they seem to last almost forever; especially if you also run an in-line paper element fuel filter (to catch the really fine dust that makes it through the original sediment bowl and screen).
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Carburators..again.

    The new O rings work great , much better than cork as they provide better seal, longer life and a much easier choke return , but like has been said, the outside of the choke benefits from polishing. I lightly sand imperfections out with 600 grit wet sandpaper and light machine oil in a honing pattern , then polishing to a high shine with steel wool and brass polish etc. Use light oil to assemble the jet and seals while out on the bench rather than try and just pull the jet out the bottom or you'll ruin the cork seals when returning the jet .

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    Re: Carburators..again.

    Thanks all. I pulled the whole thing apart and polished it up. Same problem.
    Final solution was to remove the brass washer at the top of the stack. This took a few thousandth of an inch of compression out of the spring and everything freed up.
    Car runs great!

    Question is..am I going to go to **** for leaving a part out of the carburetor?

    I think I'll get O-ring for my birthday.

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    Re: Carburators..again.

    The O-rings are a standard size; last time around I got them from a kit that ISTR was on sale for under $5 at HF. Be sure to get Buna-N (nitrile) though, as the more common EPDM won't stand up to gasoline very well.

    If it's the washer I'm thinking of, it's supposed to seal the upper jet bearing to the main carburetor body. As long as that joint doesn't leak too bad without it, seems like you would probably be fine.
    Randall
    56 TR3 TS13571L once and future daily driver
    71 Stag LE1473L waiting engine rebuild
    71-72-73 Stag LE2013LBW waiting OD gearbox rebuild

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    Re: Carburators..again.

    When you wash your car it rains. When you get your TR3A running it drops below freezing and snows...even in California.

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    Re: Carburators..again.

    Anyone have experience with the new Superdry Jet Bearing assembly offered by Moss?

    Kinda pricey, but might be worth it to avoid a lot of hassle and trial and error.370-396_2.jpg370-396_1.jpg
    Andy Blackley
    1967 TR4A CT77156L
    2015 Mini Cooper S

    Fear God and Dreadnought

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