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I give up on Kohlor Command 25


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#16 MH81 OFFLINE  

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Posted January 28, 2015 - 05:51 PM

I have a command 25 that started hard starting and backfiring and it ended up being a slightly dirty fuel filter.
Then I had to do some carb cleaning. I think I got bad gas somewhere.
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#17 glgrumpy OFFLINE  

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Posted January 28, 2015 - 06:03 PM

I have a 23 hp Kohler on my Deere. Command? don't know w/out looking, but probly.  When I mower or push snow now, I come into garage in lower throttle setting and idle it down for a little while, like 20 secs or so, then shut off. IF you just shut off at high speed and right away, you get a Big Bang in a moment. Even at slow idle it may make one small Puff before stopping. It can be quite a long pause before it does this. I figured leaner running engines now, and  hot enough to ignite what is left in engine or pulled in as it is rolling to the stop.  I will still idle down some, not shut off at throttle. My manual said nothing about shut down that I know of.

 

Last winter I didn't use to plow snow and I started once in awhile. In spring one time it was running way bad and almost like a valve problem or ??? and wondered why and what happened. Then after running a minute or two it just smoothed out and never bothered again. It was a Hmmmm moment.  Have'nt had any more incidents like that since. One thing it has always done is blow smoke on start-up if setting awhile, but cleans out real fast. Mine is vertical shaft with cylinders laying over flat then. I still think the oil in engine creeps past the rings when down and sets in the cylinders then till it starts and burns off later. It has done this since new. 


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#18 Oo-v-oO OFFLINE  

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Posted January 28, 2015 - 06:21 PM

Worst case you could always install a manual fuel shutoff valve and when you are done using the tractor just shut off the fuel and let it suck the bowl dry. 

 

I don't see what a partially sheared flywheel key would have to do with backfiring *after* the ignition is shut off... 

 

The Kohler single in my Craftsman lawn tractor has an electric fuel shutoff on the carburetor. It is there to prevent backfires by simultaneously shutting off the fuel and killing the spark when the key is turned off. When I first got it, mice had chewed off the kill wire and when you shut off the key it would continue to run for a few seconds until it drained what remained in the bowl. 


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#19 Auburn David OFFLINE  

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Posted January 28, 2015 - 06:21 PM

The reason you shut the engine down like the manual says is TO PREVENT S/D backfiring!  So if your engine had bent valve components I'll wager the Flywheel key has been stressed or partially sheared and the spark timing would be a bit off and cause the ruckus you are seeing.  Just a thought-  Check it out if you like  

I did that..even replaced the key just to be safe.



#20 Auburn David OFFLINE  

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Posted January 28, 2015 - 06:23 PM

u39c6.png

This is from the Manual.



#21 Auburn David OFFLINE  

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Posted January 28, 2015 - 06:26 PM

Thank you all..its just a mystery to me why this happens,I think if I fix it again I will figure some way to cut the spark as well as the fuel.


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#22 glgrumpy OFFLINE  

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Posted January 28, 2015 - 06:26 PM

O v O, I once had a Speedex V-twin Briggs that had fuel shut-off, and it didn't stop when key was turned and would run a few seconds and stop.  Always thought it was some "New Way" in these engines. Now wonder if I had same problem you had?? Didn't know anything about those shut-offs, never had newer engine. I just let it be, seemed to be OK and no problems.


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#23 classic OFFLINE  

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Posted January 28, 2015 - 07:57 PM

I would be tempted to turn off the ignition at full throttle to see what would happen, HA! Actually, I have an older GT5000 with the 26hp Briggs, and it will backfire if I don't let it sit at low idle before turning off the ignition.
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#24 Freddie1911 OFFLINE  

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Posted January 28, 2015 - 07:58 PM

Having raced go karts we always let the engines idle before shut down to cool down. We've got two 18 horse welders always let them idle before shut down. I have 27 horse on my craftsman, always let it idle before shut down. All my air cooled I'll let them idle to cool down. I don't recommend oils or procedures to anyone, just tell you what works for me. Freddie
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#25 Auburn David OFFLINE  

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Posted January 28, 2015 - 08:02 PM

Thank you all..I think I will fix it again..its almost a new engine...


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#26 DH1 OFFLINE  

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Posted January 28, 2015 - 08:11 PM

Sometimes it doesn't matter what you do, follow the book, do what they say and it still just doesn't work right.

They don't build stuff like they used to, they say they make it better but do they. ???

IMO fix it get it working best you can and sell it.


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#27 boyscout862 OFFLINE  

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Posted January 28, 2015 - 08:12 PM

Thank you all..I think I will fix it again..its almost a new engine...

Do a complete go through. Good Luck, Rick


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#28 boyscout862 OFFLINE  

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Posted January 28, 2015 - 08:14 PM

Sometimes it doesn't matter what you do, follow the book, do what they say and it still just doesn't work right.

They don't build stuff like they used to, they say they make it better but do they. ???

IMO fix it get it working best you can and sell it.

It seems like many of the designs are better but the quality control isn't allways there, Good Luck, Rick


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#29 olcowhand ONLINE  

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Posted January 28, 2015 - 08:35 PM

Are those push rods aluminum?  I think they are just too weak for their length.  I just don't see how a backfire would cause them to bend.  They look just like a car push rod, so wondering if you could modify one from a car engine to work.  I once had a Chevy 350 with a collapsed lifter and I didn't feel like pulling things apart to replace the lifter.  I went to a local mom/pop junkyard & got a push rod longer than my original.  I cut it off the right length to work as a solid lifter setup.  Ground the cut off rod end rounded, then as smooth as I could, then polished the end on on my lathe with emery cloth & oil.  I ran the engine for years like that & she ran like a charm.  Might be possible here???


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#30 Auburn David OFFLINE  

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Posted January 28, 2015 - 09:53 PM

Are those push rods aluminum?  I think they are just too weak for their length.  I just don't see how a backfire would cause them to bend.  They look just like a car push rod, so wondering if you could modify one from a car engine to work.  I once had a Chevy 350 with a collapsed lifter and I didn't feel like pulling things apart to replace the lifter.  I went to a local mom/pop junkyard & got a push rod longer than my original.  I cut it off the right length to work as a solid lifter setup.  Ground the cut off rod end rounded, then as smooth as I could, then polished the end on on my lathe with emery cloth & oil.  I ran the engine for years like that & she ran like a charm.  Might be possible here???

The push rods only bend because the valves are bent(both times)this engine has the lifters from a 3.0 ford engine..push rods are similar.






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