The Jack's Small Engines Forum - Join Our Online Community
Jacks Small Engines Lawn Mower & Power Equipment Forums
Reply to post

Kohler CV491s

Author
Post
Essentials Only Full Version
Raisin75
New Member
  • Total Posts : 4
  • Scores: 0
  • Reward points: 0
  • Joined: 2022/05/15 18:59:36
  • Status: offline
2022/05/15 19:07:07 (permalink)
0

Kohler CV491s

I recently bought a John Deere L110 with the Kohler CV491s. It had a blown head gasket, so I pulled the head and replaced it. Compression is great, roughly 130-150 once the ACR is not engaged. It runs ok, but has a rough spot, especially noticeable at idle. It’s not a knock, because it random. It’s more of a miss, but doesn’t really sound like a miss. I’ve replaced the spark plug. I also cleaned the carburetor, though not thoroughly like I need to. I used it last night to mow most of my yard and it did fine, but the rough sound, especially at idle, is bugging me. I need someone who’s experienced with these specific engines.
Thanks in advance.
Quote  #1

7 Replies Related Threads
    SRTsFZ6
    Super Member
    • Total Posts : 2082
    • Scores: 74
    • Reward points: 0
    • Joined: 2018/11/18 07:20:58
    • Status: offline
    Re: Kohler CV491s 2022/05/15 19:39:44 (permalink)
    0
    Most of the issues I deal with are clogged carberators...
     
    I would bet your issue is in the carb/fuel system... The parts diagram shows a pretty basic carb: 
     
    https://www.partstree.com/models/cv491-27509-kohler-command-pro-engine-made-for-john-deere-17hp-12-7kw/08-fuel-system-7/ 
     
    You can also test for spark using an in-line spark tester (maybe $10.00 on Flea Bay) but I'd do a really good carb cleaning before anything else.. 
    Quote  #2
    Raisin75
    New Member
    • Total Posts : 4
    • Scores: 0
    • Reward points: 0
    • Joined: 2022/05/15 18:59:36
    • Status: offline
    Re: Kohler CV491s 2022/05/15 21:36:56 (permalink)
    0
    Thanks for the response. I know I need to clean the carburetor and I certainly will. The engine just doesn’t sound like what I’m used to hearing from a clogged carburetor. It sounds like more of a miss.

    I removed the kill wire from the coil, thinking I might have had an intermittent short, but that didn’t make any difference, so I’ll clean the carb this week.
    Quote  #3
    Raisin75
    New Member
    • Total Posts : 4
    • Scores: 0
    • Reward points: 0
    • Joined: 2022/05/15 18:59:36
    • Status: offline
    Re: Kohler CV491s 2022/05/18 21:25:40 (permalink)
    0
    I cleaned the carburetor really well this evening. I also pulled the head again to double check that both valves are seating properly, and they are. I put everything back together and nothing has changed.

    I’m wondering if the ACR on the cam is acting up, because a coworker, who is very good with engines seemed to think the exhaust valve was leaking based on a video I took of it running. Do the ACR on these cause issues sometimes?
    Quote  #4
    SRTsFZ6
    Super Member
    • Total Posts : 2082
    • Scores: 74
    • Reward points: 0
    • Joined: 2018/11/18 07:20:58
    • Status: offline
    Re: Kohler CV491s 2022/05/19 08:17:00 (permalink)
    0
    I'm not familiar with the ACR on this Kohler. If it's anything like a Briggs, those come apart and cause hard cranking.   Once running, no issues. 
     
    I would do a leak down test, (cam just past the bump),  TDC, on the compression stroke.
     
    This will definitly tell you if either valves are leaking.
     
    If the head is still off, put the plug back in, flip upside down and fill with fluid (I use gas).  If leakage occures past the valves, it needs clean up/valve job.
     
    Another way to check the valves, head still off, fully assembled, you should NOT be able to spin the valve in the head with your thumb...
    Quote  #5
    Raisin75
    New Member
    • Total Posts : 4
    • Scores: 0
    • Reward points: 0
    • Joined: 2022/05/15 18:59:36
    • Status: offline
    Re: Kohler CV491s 2022/05/19 11:14:23 (permalink)
    0
    Hi SRTsFZ6,
    While I had the head off, I put in on the bench with the valves up, covered the valves with water and let sit for 20 minutes. There was ZERO water past the valves, intake or exhaust during that time. The issue is not the valves directly. This is why I'm wondering if the issue is with the ACR, intermittently causing the exhaust valve to open "extra" during compression stroke. When I kill the engine, I hear a couple of metallic "tinks" when the engine gets to slower RPMs before it stops spinning. Wonder if that's the ACR moving. Is the spring off or broken or???
     
    It will probably be a few days before I can remove the engine and turn it over to open it up. I'm surprised there's not more conversation here about this. I'm sure someone has had a similar problem.
     
    Dee
    Quote  #6
    SRTsFZ6
    Super Member
    • Total Posts : 2082
    • Scores: 74
    • Reward points: 0
    • Joined: 2018/11/18 07:20:58
    • Status: offline
    Re: Kohler CV491s 2022/05/19 12:58:54 (permalink)
    0
    Myself and another person are pretty much the only one's responding to new posts.
     
    Sounds like the head is good and I agree, time to look at the cam...
    Looks somewhat similar to the Briggs. 
     
     Of course, anything can fail..
    Please post back what you find
     
    Looking up at different parts sites, seems that cam is discontinued..  :(
     
     

    post edited by SRTsFZ6 - 2022/05/19 13:04:53

    Scott
    Quote  #7
    Mikel1
    Moderator
    • Total Posts : 1174
    • Scores: 41
    • Reward points: 1
    • Joined: 2016/04/14 18:48:53
    • Location: Georgia
    • Status: offline
    Re: Kohler CV491s 2022/05/19 19:15:24 (permalink)
    0
    SRT, I deleted some of your posts. My apologies if I accidentally deleted one you needed, had a lot of Chinese to delete at that time
    Quote  #8
    Jump to:
    Copyright © 1994 - 2016 Jacks Small Engine & Generator Service, LLC
    © 2025 APG vNext Trial Version 5.5