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John Deere JS63 won't start - backfires....

9554 Views 5 Replies 3 Participants Last post by  Basementgeek
I have a John Deere JS63. It was given to me with the information that it wouldn't start due to a dirty carb and that the carb just needed to be cleaned.

So....I bought a new carb and air filter fuel gas ignition coil....and new spark plug. It still will not start and backfires when trying to do so....:rolleyes:

Any idea's???? What else should I look at?:4-dontkno
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What kind of engine does it have on it? Model numbers?

Also, check the flywheel key. May be sheared or partially sheared.
Briggs & Stratton
Model Series 121602, Intek
6.75 hp
Cycle 4
Over Head Valve

Gonna check the flywheel now key now....will report back in a few.
Well, won't get to check the key till tomorrow....don't have a 15/16 socket.:rolleyes: So am borrowing one from a buddy of mine....will post up with my results.
Had to wait till payday to go buy a new set of sockets....

Pulled everything off and the key looks fine....and other idea's. Really need to get this mower going.

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Have you ever adjusted the vales?

If not, here is how to do it:

Repair Videos

Scroll down to valve adjustment to watch the video.

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