Jump to content

Nominations for Tractor of the Month
Garden Tractors and Parts on eBay



Photo
- - - - -

I give up on Kohlor Command 25


  • Please log in to reply
47 replies to this topic

#31 Oo-v-oO ONLINE  

Oo-v-oO

    New Member

  • Senior Member
  • Contributor
  • Member No: 5162
  • 340 Thanks
  • 448 posts
  • Location: Live Free or Die, USA

Posted January 28, 2015 - 10:03 PM

Both exhaust valves and not the intakes, I would assume? 

 

I'm guessing the pressure pulse from the backfire pushes the valves open so far the piston smacks them and bends them. 


  • Auburn David said thank you

#32 superaben OFFLINE  

superaben
  • Senior Member
  • Contributor
  • Member No: 11204
  • 7,664 Thanks
  • 5,677 posts
  • Location: Shenandoah Valley, VA

Posted January 28, 2015 - 11:42 PM

First of all, the engine has to be shutting off the fuel at the solenoid while at the same time killing the spark.  If you have spark while the key is in the off position, you have a problem with the tractor wiring that needs to be fixed. 

 

What oil are you running in the engine?  Kohler calls for 10w30 and since the Command has hydraulic lifters, I would follow Kohler's recommendations. 

 

Ben W.


  • Auburn David said thank you

#33 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,646 Thanks
  • 29,840 posts
  • Location: South Central Kentucky

Posted January 29, 2015 - 05:59 AM

Both exhaust valves and not the intakes, I would assume?

I'm guessing the pressure pulse from the backfire pushes the valves open so far the piston smacks them and bends them.


Oh, gotcha! And spark not needed with hot muffler internals.
  • Auburn David said thank you

#34 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,455 Thanks
  • 6,623 posts
  • Location: Bangor Pa

Posted January 29, 2015 - 06:19 AM

Would the back fire be from un-burnt fuel in the hot exhaust igniting,  kind of like as a kid ,, shutting the key off on a stick shift car then turning it back on " BOOM"  lol


  • Auburn David said thank you

#35 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,646 Thanks
  • 29,840 posts
  • Location: South Central Kentucky

Posted January 29, 2015 - 06:39 AM

Would the back fire be from un-burnt fuel in the hot exhaust igniting, kind of like as a kid ,, shutting the key off on a stick shift car then turning it back on " BOOM" lol


Yep, gotta be.
  • Alc and Auburn David have said thanks

#36 skyrydr2 ONLINE  

skyrydr2

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 5032
  • 3,412 Thanks
  • 3,163 posts
  • Location: Gardner, Massachusetts!

Posted January 29, 2015 - 07:16 AM

If your fuel shutoff valve is sticking, and they do big time... BANG!! And I have seen them bend a rod doing this,both connecting rod and pushrods so make sure that thing is working or let it idle for a few minutes then shut it down . I have always shut mine down after a cool down period and never had a bang.
  • Auburn David said thank you

#37 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,646 Thanks
  • 29,840 posts
  • Location: South Central Kentucky

Posted January 29, 2015 - 07:26 AM

If your fuel shutoff valve is sticking, and they do big time... BANG!! And I have seen them bend a rod doing this,both connecting rod and pushrods so make sure that thing is working or let it idle for a few minutes then shut it down . I have always shut mine down after a cool down period and never had a bang.


I always idle a couple minutes to cool a gas engine's exhaust too. When I forget.....BANG every time.
  • Auburn David said thank you

#38 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,455 Thanks
  • 6,623 posts
  • Location: Bangor Pa

Posted January 29, 2015 - 08:31 AM

Back to a question I had about , "why would they want you to shut it off at 1/2 throttle ?"   Would  it be to push more air through the exhaust at  shut off ?


  • Auburn David said thank you

#39 Auburn David OFFLINE  

Auburn David
  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 61865
  • 2,754 Thanks
  • 1,962 posts
  • Location: Alabama

Posted January 29, 2015 - 11:50 AM

Back to a question I had about , "why would they want you to shut it off at 1/2 throttle ?"   Would  it be to push more air through the exhaust at  shut off ?

Thats just what they recommend on these engines..I have had two folks (the sears tech,and a small engine mechanic)tell me that these engines do not kill the spark..only the gas.


  • Alc said thank you

#40 Auburn David OFFLINE  

Auburn David
  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 61865
  • 2,754 Thanks
  • 1,962 posts
  • Location: Alabama

Posted January 29, 2015 - 11:52 AM

1/2 throttle shut off is only for the engines with the fuel shut off valve,low idle is used for the ones with standard carb and EFI.


  • Alc said thank you

#41 KennyP ONLINE  

KennyP

    FORDoholic

  • Super Moderator
  • Staff
  • -GTt Supporter-
  • Contributor
  • Member No: 2253
  • 28,461 Thanks
  • 39,690 posts
  • Location: Collinsville, Oklahoma

Posted January 29, 2015 - 04:46 PM

Ain't no way I'll shut off any engine at half throttle!


  • Auburn David said thank you

#42 Auburn David OFFLINE  

Auburn David
  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 61865
  • 2,754 Thanks
  • 1,962 posts
  • Location: Alabama

Posted January 29, 2015 - 05:46 PM

Ain't no way I'll shut off any engine at half throttle!

Just going by what they say to do..I think its a bad design myself.


  • KennyP said thank you

#43 olcowhand ONLINE  

olcowhand

    Red Tractor Nut & Diesel Addict

  • Staff Admin
  • Staff
  • -GTt Supporter-
  • Sponsor
  • Contributor
  • Member No: 20
  • 35,646 Thanks
  • 29,840 posts
  • Location: South Central Kentucky

Posted January 29, 2015 - 06:07 PM

It's your hot muffler's guts that is igniting the explosion.  If there was still spark to ignite fuel getting past a faulty fuel solenoid, then it would burn that fuel in the combustion chamber.  BUT, if (and spark should be cut off) fuel is getting past the solenoid, it gets pumped right on through to a very hot muffler, which sets off the explosion inside the muff.  The only way to avoid the possibility is to let the engine slow idle for a couple minutes.  None of my gas engines have the fuel solenoid and as long as I idle to cool the muffler, I never have a backfire.  But when I forget, it's almost guaranteed.


  • Alc, KennyP and Auburn David have said thanks

#44 Oo-v-oO ONLINE  

Oo-v-oO

    New Member

  • Senior Member
  • Contributor
  • Member No: 5162
  • 340 Thanks
  • 448 posts
  • Location: Live Free or Die, USA

Posted January 29, 2015 - 09:47 PM

I have had two folks (the sears tech,and a small engine mechanic)tell me that these engines do not kill the spark..only the gas.

 

 

 Man, I find that very hard to believe. 


  • Auburn David said thank you

#45 Alc ONLINE  

Alc

    Tractorholic

  • Senior Member
  • -GTt Supporter-
  • Contributor
  • Member No: 1094
  • 5,455 Thanks
  • 6,623 posts
  • Location: Bangor Pa

Posted January 30, 2015 - 06:19 AM

 

Man, I find that very hard to believe. 

Me neither , maybe someone could check this out some time .


  • Auburn David said thank you




Top