John Deere JS46 Hard Starting Problem

mgilbert

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Aug 2, 2013
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I have a three year old John Deere JS46 walk behind mower with a Briggs Engine. The mower has had very little use. Lately, it has gotten harder and harder to start. Fresh fuel, clean air filter, new spark plug... It takes several hard pulls on the cord, and it usually just makes a ffffft ffffft ffffft sound, and it sometimes backfires. After a few pulls, it'll hit a time or two, then finally catch, miss some, slowly build up to speed, and then finally start running fine. If I shut it off hot, it is just as hard to start as it was cold. I'm not sure if this is related, but when it is running, the engine will often surge and run fast briefly when under load.

This engine seems to have an easy start feature that floats the valves to reduce compression when the cord is pulled??? If so, it almost seems as if the valve isn't closing so the engine can start. Sometimes, it acts as if it is flooded. I just can't any obvious problem.

Does anyone have any ideas?
 

mgilbert

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I have a three year old John Deere JS46 walk behind mower with a Briggs Engine. The mower has had very little use. Lately, it has gotten harder and harder to start. Fresh fuel, clean air filter, new spark plug... It takes several hard pulls on the cord, and it usually just makes a ffffft ffffft ffffft sound, and it sometimes backfires. After a few pulls, it'll hit a time or two, then finally catch, miss some, slowly build up to speed, and then finally start running fine. If I shut it off hot, it is just as hard to start as it was cold. I'm not sure if this is related, but when it is running, the engine will often surge and run fast briefly when under load.

This engine seems to have an easy start feature that floats the valves to reduce compression when the cord is pulled??? If so, it almost seems as if the valve isn't closing so the engine can start. Sometimes, it acts as if it is flooded. I just can't any obvious problem.

Does anyone have any ideas?

Really disappointed that so many people looked at this and didn't offer any advice... After checking everything, I began to think that it sounded like a timing problem. Turned out to be that the flywheel was a few degrees out of position because the key was sheered - a simple problem to fix!!! Keep that in mind if you ever run into something similar...
 

Carscw

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Really disappointed that so many people looked at this and didn't offer any advice... After checking everything, I began to think that it sounded like a timing problem. Turned out to be that the flywheel was a few degrees out of position because the key was sheered - a simple problem to fix!!! Keep that in mind if you ever run into something similar...

Sorry no one helped you. It has got to the point that people on here don't want to help for fear of getting insulted by the so called small engine master techs on here.

(( cowboy up and get over it ))
 

mgilbert

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Sorry no one helped you. It has got to the point that people on here don't want to help for fear of getting insulted by the so called small engine master techs on here.

(( cowboy up and get over it ))

I understand. Thanks... At least I was able to solve the problem.
 

Tiphanie

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Really disappointed that so many people looked at this and didn't offer any advice... After checking everything, I began to think that it sounded like a timing problem. Turned out to be that the flywheel was a few degrees out of position because the key was sheered - a simple problem to fix!!! Keep that in mind if you ever run into something similar...

Hi. I have the same problem with mine. Where is this flywheel located? My mower just went out of warranty. I have maybe used it 15x in 3 years.
 

common sence

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I understand. Thanks... At least I was able to solve the problem.

you should have been honest from the start, and told us that you ran over a rock or stump and stalled the mower. that's how flywheel keys get sheared they don't just up and say one day "I think I will shear today" you hit something hard with a mower you usually tear things up. you lead me to believe it just on its own got hard to start when actually you tore it up.
 

common sence

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Hi. I have the same problem with mine. Where is this flywheel located? My mower just went out of warranty. I have maybe used it 15x in 3 years.

did you find the problem with your mower. I know I am a little late but I recently bought a js 46 used that would not start and have become a self made professional on this mower. the easy start system is a bad cheap design. but curious what you found out about yours.
 

jenkinsph

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you should have been honest from the start, and told us that you ran over a rock or stump and stalled the mower. that's how flywheel keys get sheared they don't just up and say one day "I think I will shear today" you hit something hard with a mower you usually tear things up. you lead me to believe it just on its own got hard to start when actually you tore it up.



You might be correct that hitting an object that stalled the mower is what likely caused the key to shear but your wording is too harsh. Try to lighten up a bit, at least the OP was resourceful enough to dig in and find the problem on his own.
 
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