8HP Briggs Horizontal starts then dies

Discussion in 'Mechanic and Repair' started by Korey, Oct 11, 2007.

  1. Korey

    Korey LawnSite Senior Member
    Messages: 269

    Tried searching, but no avail. Got an almost new Briggs 8hp on a Troy Bilt horse that won't stay running unless the choke is constantly switched on/off and when so, it runs pretty rough. When you let go of the choke no matter what position it is in, it will die unless switched back and fourth fast.

    Took out both adjusting screws and the tips are pointed but then flatten out at the bottom rather than being pointed like a needle. Does this have anything to do with the problem? Model nbr is 194412- thanks.
  2. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    Almost new?
    Depending on the Type#, the latest IPL for that engine is 1992 or 1997!

    Your problem indicates a lean condition.
    Most likely you have severe vacuum leaks or the passage that the high speed needle controls is blocked.

    A flat tip on the needles isn't right either, but I would think that by just backing out the screws far enough, that you could get it to run off choke. That doesn't mean it would run well, but at least run with the choke off.
  3. Korey

    Korey LawnSite Senior Member
    Messages: 269

    Yeah I got it from the Small Engine Warehouse so it was probably an older model they had left over. I'll try backing out the screws to see what happens, but the tips definitely should be pointed? The engine came with a one year warranty which expires Oct 30... lol.
  4. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    What's the code# on it? That's the DOM, YYMMDD.
    Also the Type# would be handy.
  5. Korey

    Korey LawnSite Senior Member
    Messages: 269

    I should have brought the notepad that I wrote the numbers down on from my friend's house... Will try to get it tomorrow. Thanks for the reply.
  6. KathysLGC

    KathysLGC LawnSite Bronze Member
    Messages: 1,345

    It def sounds like a carb issue or cracked hose issue. Did it just start doing this? Does it have a govener spring that came off?
  7. khouse

    khouse LawnSite Bronze Member
    Messages: 1,465

    If you can't get it to run by backing out the main needle then take the carb off, dismantle it, spray it out with 3m brake cleaner, blow out with compressed air and reassemble. Then clean out the fuel tank and add fresh fuel. Turn both adjustment needles all the way in (not too hard) then back both out 1.5 turns and see what happens.
  8. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Brigg's that have been sitting (and other engines as well) are famous for getting the float inside the bowl stuck, I'd be for pulling that apart when you clean the carb, and make sure the float mechanism and all that gets sprayed and cleaned up, also don't forget to send something through the jets as well.

    On the jets, inspect visually to see if you notice any debris stuck in there.
    Obviously most you can't look through the tube, but sometimes there's a bit stuck at the inlet or outlet, looks a lot like when a pump sprayer nozzle gets debris in it, just some piece of crap won't come out, check for this.

    Other than that my favorite method is carb cleaner, let it sit for a bit, then jets of compressed air (watch your eyes thou).
    If you don't have compressed air, follow with more carb cleaner spray, then let drip / air dry.

    Also, you might want to see if your machine has an inline fuel filter on that rubber tube from tank to carb.
    If it doesn't (mine didn't), it's worth the $1 -$3 to install one anyway, might have to fabricate a little.

    Oh, one more thing, the diaphragm might be brittle or stiff and must be replaced, if it still doesn't work after all of this you can get one of these, but you can check this thing while you got the carburetor off.
  9. Korey

    Korey LawnSite Senior Member
    Messages: 269

    Thanks for the replies. Gas tank was drained and fresh gas added. Carb bowl and ajustment needles were taken out and inspected everything was clean, so that's why I doubt the carb is dirty or clogged although a part may have gotten stuck. However, what about the adjustment needles not being sharp?

    Topsites- I like your new quote. I'm a fan of Ferraris myself.

  10. Bill Kapaun

    Bill Kapaun LawnSite Senior Member
    Messages: 956

    You still haven't provided the TYPE number!
    Go to the Briggs site and download an IPL for your engine.
    Make sure part# 113 is clear.

    Thinking about a flat tipped needle. It kind of depends on HOW FLAT.

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