Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors


Simplicity GTHL 17 Revving High

Recommended Posts


Hey guys, I have a Simplicity GTHL 17.

I love this tractor, but for some reason it just wants to rev as hard as it can, I mean, maxes itself out like its trying to take off in flight.

I had a friend who is better than me with mechanics, we all have that friend, and he seems to think that the govenor might be broken internally.

Any thoughts on what could be causing this?

It all started after I took the carb of to clean, and replaced the coil with a dynatek.

Thanks in advance for the help guys.

Share this post

Link to post
Share on other sites

Could be internal, but first check the governor and throttle linkage and springs.  It could be something as simple as a broken throttle return spring.

Share this post

Link to post
Share on other sites

@Brettw is one of the KT experts on the site.  I believe there's an internal plastic gear that craps out.  But as @wwbragg said, it could be something simple. 

Hopefully Brett will chime in on your problem.  


Share this post

Link to post
Share on other sites

Do you have any throttle control with the throttle lever?  Will the engine idle or does it run wild?   Ifyou had the carb off you may now have the linkage not connected correct, or you lost the throttle stop position.  There is a throttle stop that needs to be adjusted for max 3600 rpms.

Go there first.

  • Like 1

Share this post

Link to post
Share on other sites

Hello, Tim, welcome aboard!


The KT's and Magnums do have a nylon governor gears that are know to potentially fail.  They are still available and can be found in numerous places for about 45 bux.  E-bay for one.  However, before I would jump to that, I would at least make sure the governor is set correctly (although, unless someone has messed with the linkage or governor arm I can't see how it would be out of whack).  I would start by making sure nothing is impeding the governor arm assembly.  Then, if you go to the Kohler site, they have owners and service manuals for their engines.  The service manual is very detailed and specific and will give you directions to set the governor.  I would follow those directions and see if there is any change.  However, I would warn that once those gears go to pieces, there are parts that could be flying around internally, and can be catastrophically  damaging to the engine.  The process to replace the gear is fairly involved and requires a complete tear down of the engine, at which time I would recommend a set of rings at a minimum.   Anyway, good luck, and any more questions, just reach out.  Welcome again!

  • Thanks 1

Share this post

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Who's Online (See full list)

    • MARK (LI)
    • s_stephen
  • Today's Birthdays

    No users celebrating today
  • Recent Status Updates

    • Paul M.Murphy

      Paul M.Murphy

      Hello glad I got on this site. I hope to upload a couple of photos of my Simplicity Broadmoor 
      Model 707 Tractor. I have replaced all the belts on it and installed a new ignition switch.
      Have a mower deck which was in poor shape , repaced a couple of bushings and welded the
      deck where there was some holes. The tractor and mower deck came from a friend and the 
      mower deck metal was getting pretty thin. Some new metal was put in it and we also undercoated the underside of the deck. This was done by my friend Greg Toulman.
      I have not put the mower deck on the tractor yet, waiting for Greg to come home and give me a hand. Can you please tell me if there is a manual for the mower deck and where I could get one.
      I would also like to get some moon wheel discs as well.
      I will try and down load some photos of the tractor when my wife shows me how to. 
      I really love driving this tractor and also how well it is made compare today's tractors, especially the flexible rear end and the rollers.
      Tell the next time 
      · 9 replies
    • jbrooks

      jbrooks  »  Talntedmrgreen

      folowing  this from a link at the downloads.  I just rescued an AC 920 with the lambodini diesel. I can' t download  yet .  Where did you find the PDF copy you posted. . I would like to figure out how to adjust the injection pump. 
      I assume it's a bosche, correct
      · 0 replies
  • Adverts