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No start B&S 6.5hp Craftsman mower

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Gregb7
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2017/09/05 18:49:04 (permalink)
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No start B&S 6.5hp Craftsman mower

Hey! Trying to fix my uncle's mower.
It's a craftsman 6.5hp Briggs mower.

I've tried everything and can't get it to start.

I know it's getting a good spark and I've used starting fluid in the carb and also tried spraying in cylinder. Nothing happens. Replaced ignition coil and flywheel sheer key. Have new carburetor but haven't put it on yet because I don't believe it's a fuel issue. New air filter and new spark plug.

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    AVB
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/05 20:35:23 (permalink)
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    Do you have spark?
    Roy
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/05 22:20:12 (permalink)
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    Disconnect the spark plug, tie the engine bail lever down then give the blade a flip backwards. If it doesn't bounce back when it hits compression you have found your problem. A leak down test is more sophisticated but not everyone has the tool.
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/06 09:22:55 (permalink)
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    Ok thanks. I'll try after work.
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/06 17:01:16 (permalink)
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    Just gave it a shot and unfortunately I'm guessing it's a compression issue. Does not bounce back. I was able to feel the compression but at no point did it have enough to push back the blade.

    I did the same test on my mower that runs great to make sure I was doing it right and the good mower bounces back.
    Mikel1
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/06 20:39:09 (permalink)
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    I would check the travel of the valves, assuming piston is moving. Leak down tester is definitely faster at diagnosing, compression tester is also useful though.
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/07 18:59:28 (permalink)
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    What would be the odds of it having low compression due to a bad head gasket but the head gasket not leaking oil? Not possible? Going to start tearing into it tonight but I'm thinking he just wants to toss the mower if it's because of the rings or valves.
    Mikel1
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/11 16:48:39 (permalink)
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    I would make sure valves are sealing, not stuck open/closed first. If you take off head best to replace head gasket.
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/12 20:53:41 (permalink)
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    Took head off and the side valve cover. Exhaust valve seems to be moving fine. Intake valve moves as well but not nearly as much compared to exhaust valve. Also seems like it may not be seating completely. What could cause this besides carbon buildup?
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/14 21:08:08 (permalink)
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    I believe I found the issue. The intake valve seat seems to have started to come out. I tapped it back in but I'm assuming I'd be better off buying a new one. I can't test it out yet because I can't get the spring back in without a compressor. I tried without one numerous times and i just can't get it.
    Roy
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/15 11:26:01 (permalink)
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    Stake the seat in three places with a center punch then peen the aluminum around the seat with a flat punch. Would a local rental yard have a small automotive type compressor? If you can't beg, borrow, or steal one it's a trip to Autozone.
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/16 14:28:11 (permalink)
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    I got it up and running finally! Thanks for the help. I staked the seat in place. As for the valve spring I used to small zip ties to compress the spring and was able to get the valve in. Then cut zip ties. Took a few tries to get it. Put it all back together started with 2 pulls and ran good. I let it run for 10 minutes and now it's cooling off. Going to start it again after it's cool to make sure it's still good before I give it back. Thanks again for all your help everyone!
    Mikel1
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/19 13:46:44 (permalink)
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    So how's it doing now?
    Taryl fixes all has a video on staking seat, link below if anyone is interested.
    https://www.youtube.com/watch?v=GTEVXl0uxHg
    Gregb7
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/19 15:25:37 (permalink)
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    Thanks. So far it's good. Gave it back to him and it's been used once without issue
    Mikel1
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    Re: No start B&S 6.5hp Craftsman mower 2017/09/19 20:42:04 (permalink)
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    Thanks for the update.
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