# Briggs 5 hp mower wont stay running



## jdunn (Apr 8, 2010)

*Briggs 6.5 hp mower wont stay running - HELP before I kill it!!!*

I have a sears push mower with a 6.5 hp B&S motor. It wouldn't start before an I was told the carb needed to be cleaned and the seal around the bowl needed to be replaced. So I ordered a new carb and installed it and have the same problem. I sprayed carb cleaner in it and it will start, but only run a few seconds (until the cleaner burns off. I know gas is flowing to the carb, but I'm at a loss after that. So I cleaned the old carb, used the bowl gasket on the old one and the exact same thing is happening. I'm stumped, getting pissed and frustrated. Engine model 123K05-0275-E1 Any ideas? ANY advise would help.

Thanks


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## indypower (Apr 8, 2009)

Please post the engine numbers.


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## jdunn (Apr 8, 2010)

Sear model # 917.378380, code 123K05-0275-E1-03020656 AND I corrected the engine size. It is a 6.5 hp Briggs


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## indypower (Apr 8, 2009)

First try a new spark plug. Then check the flywheel key. A sheard flywheel key will cause the timing to be off. If you pull it over by hand and it trys to pull your arm back, the key is sheared. Common problem on push mowers as they seem to hit rocks, roots, etc and that will shear the flywheel key.


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## jdunn (Apr 8, 2010)

It runs great for the few seconds it does run and it typically starts on the second or third pull after spraying the carburetor with cleaner. It just seems like it's not getting gas. I know it's making it to the carburetor, just not to the cylinder. When I push the prime button I hear air where I thought I use to hear fluid, is this right? Could something be blocking the fuel in the carburetor since it's brand new?


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## dehrhardt (Apr 1, 2009)

There is a known priming issue with these engines. With the air cleaner off, look into the throat of the carb while you push on the primer. You should see gas squirting up from the nozzle. If not, doubling up on the gasket between the air cleaner base and the carb often will take care of it. Don't overtighten the air cleaner base screws or the base will warp more.

In cold weather you may have to prime it and start it a few times to get it running. Make sure the o-ring onto the intake manifold is good - if in doubt, use a new one.


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## jdunn (Apr 8, 2010)

OK, I doubled up on the gaskets and it is priming. I know this because the only way to keep it running is by continually pushing the primer. As soon as I stop pushing the primer, the engine stops. What could be causing this to not get gas? I tried it with a brand new carburetor and the old carburetor and it's all the same.


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## glenjudy (Aug 26, 2006)

Sounds like fuel is not being pushed up the main jet. The bowl nut has a couple of orifices, one on the top and one on the side. Spray carb cleaner thru side orifice, should squirt out the top, and vice-versa.
HTH


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## indypower (Apr 8, 2009)

glenjudy is correct. Just make sure you drain the gas tank first so all the gas does not drain out of the gas tank. Just pull the "bolt" off the bottom of the carb. Use a small piece of wire like a twist tie from a loaf of bread. Make sure to strip the plastic off the tie. Use that to clear the holes. There is 1 large hole near the bottom and 1 or 2 tiny holes higher up. 1 hole may be in the threads. Everyons misses that 1. It is usually the tiny holes that are clogged up enough that you would not even know they were there.


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## jdunn (Apr 8, 2010)

FINALLY!!! Thanks to EVERYONE for their assistance! I cleaned out the side and top orifice with some wire, re-assembled and tired it and same thing. Then I remembered have a spool of small wire my dad had over 30 years ago (I'm a single dad so we don't know what a twist tie is, you spin the bread and tuck in under the loaf). I could tell immediately the smaller wire went further in and I could see it through the side orifice. Ran it in and out several times and sprayed with carburetor cleaner, re-assembled and it ran like a champ and all is well.

Thanks again to everyone for their assistance. Great group and forum!!


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## indypower (Apr 8, 2009)

Glad we could help you.


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