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Lawn mower won't start

Posted by cmilot6329 Arizona (My Page) on
Tue, Aug 5, 14 at 23:40

Craftsman 6.25 HP 21" blade Briggs and Straton Motor
model: 917.378860

I'm having issues with my push behind mower. It worked fine few weeks ago. When I went to start it about a week ago it ran for about 5 seconds then just died. Started back up for about a second and then immediately died. Now it won't even start.

I've been reading and searching the past week and can't seem to fix it. Things I've tried:

1. Checked for spark and has good spark
2. Completely removed carb and cleaned inside and out. Removed float, needle, bowl, nut and cleaned with carb cleaner. They were pretty much spotless to begin with but used twisty tie wire to clean all the little passages.
3. Sanded down flywheel and clutch legs as they were kinda rusted.
4. Checked fuel line from tank to carb and it flows just fine.
5. Watched through throttle plate as I primed and it is pulling fuel in. What is weird is that when I spray carb cleaner into the carb when the air filter is removed I can get it start for a split second but then it dies.

Anyone have any other ideas on what could be causing this or what I can try?

Thanks for the help!

Follow-Up Postings:

RE: Lawn mower won't start

Engine should be a -

Remove the Brass Nut holding the carb bowl on.
That is your Main Jet.
Clean the holes with a fine wire such as a tie wrap from a loaf of bread.

RE: Lawn mower won't start

Yes I have done that several times. There was no gunk in it at all but I did clean the 2 holes near the threads and the one on the top with a fine wire. Any other suggestions?

Another thing to note, it does not start when I use the priming bulb however I can see gas coming up out of the spout. It only works if I spray carb cleaner deeper inside.

This post was edited by cmilot6329 on Wed, Aug 6, 14 at 11:32

RE: Lawn mower won't start

Stop wasting your time trying to clean the carb, A new one is about $40-45 and attempting to clean all the passages without a sonic cleaner is next to impossible. save yourself from the frustration and buy a new carb, You mentioned the primer so for that engine with primer carb the PN sould be 799868 and runs about $40, check amazon, Lawnmower Partsman is a great dealer on there. Hope this helps Good luck

RE: Lawn mower won't start

A couple of things. One, is the fuel you are using gasoline? If you can see it inside the carb venturi and it either can't burn it or draw it in -that might lead you to a way to go.Two, if you were to remove the bowl and unclamp the fuel line, do you get a steady stream of fuel? If not- new float valve kit. Three, the intake manifold (tube) and seals secured and not cracked?

RE: Lawn mower won't start

Thanks for the replies! Was ready to order a new carb off amazon for $30 but decided to take the carb completely off again and clean it for the 2nd time instead of just cleaning the bowl/nut. Seems to be working fine now. If it acts up again will just replace teh entire carb assembly.

Thanks again for the advice!

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