acc7484 52 #1 Posted September 30, 2021 Hello All. I have a 312-8 Wheel Horse with a Kohler M12. The other day I was mowing the lawn and all of a sudden the engine revved up real high. The governor was not loose. Everything seems to be in place. I loosened the nut and checked the adjustment of the governor according to the manual However it still over revs. Could this be an internal problem . Am I missing something? Any help or guidance would be appreciated. Thank you. Share this post Link to post Share on other sites
Maxwell-8 4,358 #2 Posted September 30, 2021 is your carb valve closing on the lowest trottle setting? Share this post Link to post Share on other sites
Skwerl58 729 #3 Posted September 30, 2021 My 414-8 went high rev and a plastic throttle linkage bushing had failed. Ordered three and installed two and that fixed it. Hope you get this solved soon. 1 Share this post Link to post Share on other sites
acc7484 52 #4 Posted September 30, 2021 Yes Maxwell, The carb is closing and has a nice slow Idle. As soon as you give it a little throttle it goes full tilt .... Very hard to control. Share this post Link to post Share on other sites
WHX?? 49,467 #5 Posted September 30, 2021 Try seeing if the guv arm has restistance against a finger as she is reved abit. First thing that comes to mind here is the flag on the guv shaft that the guv weights push against broke off inside. I have seen that happen. Share this post Link to post Share on other sites
acc7484 52 #6 Posted October 1, 2021 OK .... ill check on that tomorrow. Is that part available? Share this post Link to post Share on other sites
Gregor 4,847 #7 Posted October 1, 2021 (edited) Do you have a spec # on that motor? Possibly..... Spec # 421527 Edited October 1, 2021 by Gregor 1 Share this post Link to post Share on other sites
WHX?? 49,467 #8 Posted October 1, 2021 11 hours ago, acc7484 said: OK .... ill check on that tomorrow. Is that part available? If that's what it is should be plenty available off parts motors. I know on the K series the flag is just staked on a flat on the shaft and that's where it comes loose. Not sure what M series has and almost think the guv gear is plastic? Just thinking out loud here if the flag came off one should be able to spin the shaft 360 deg. right?? Let us know what you find. Share this post Link to post Share on other sites
Gregor 4,847 #9 Posted October 1, 2021 (edited) 1 hour ago, WHX?? said: Just thinking out loud here if the flag came off one should be able to spin the shaft 360 deg. right?? If the flag did indeed simply fall off, I believe you are right. As a caution, I would not run the engine again, until you find out if the flag did fall off. If it did, it may be laying harmlessly in the bottom of the pan. Then again, it may not be. Edited October 1, 2021 by Gregor Share this post Link to post Share on other sites
Gregor 4,847 #10 Posted October 1, 2021 12 hours ago, acc7484 said: OK .... ill check on that tomorrow. Is that part available? Yes, readily available. Share this post Link to post Share on other sites
pfrederi 17,969 #11 Posted October 1, 2021 16 minutes ago, Gregor said: Yes, readily available. Yes readily available...of course you have to completely tear down the engine to replace it. Share this post Link to post Share on other sites
acc7484 52 #12 Posted October 1, 2021 (edited) OK Folks.... When at 1/3 throttle (that relaxes the spring to the linkage) I can push the linkage over and it has little resistance. It would seem to me that it should be a little more but I really don't know. The linkage and springs on the outside look to be OK. The shaft will turn clockwise and will stop turning counter clockwise. I adjusted the linkage by turning the shaft counter clockwise till it stopped. Them moved the lever counter clockwise all the way as well and tightened the nut. Edited October 1, 2021 by acc7484 Share this post Link to post Share on other sites
Gregor 4,847 #13 Posted October 1, 2021 12 minutes ago, acc7484 said: I adjusted the linkage by turning the shaft counter clockwise till it stopped. Them moved the lever counter clockwise all the way as well and tightened the nut. And did that work? Share this post Link to post Share on other sites
acc7484 52 #14 Posted October 1, 2021 No difference it still over revved.. Share this post Link to post Share on other sites
Gregor 4,847 #15 Posted October 1, 2021 I know of no way to inspect the governor internals, without tearing it down. Nor am I familiar with an MV series engine. Hopefully, someone smarter will chime in. Share this post Link to post Share on other sites
pfrederi 17,969 #16 Posted October 1, 2021 (edited) That you r governor shaft stopped when you turned it counter clockwise would indicate he stop pin was not broken. Check and make sure the small tab on the linkage contacts the high speed set screw ( blue circle) when throttle is wide open. if it does make a major adjustment to the high speed stop run it up about half way. Then see if the over rev continues. If it still wants to over rev then there maybe something wrong internally. The sudden onset leans toward something breaking.... Edited October 1, 2021 by pfrederi Share this post Link to post Share on other sites
acc7484 52 #17 Posted October 1, 2021 This tractor always ran slow. I never adjusted the high speed setting. From what I can see the lever does not reach the top of the screw head at full throttle. Its painted in place. Im leaning towards an internal issue. I shut it down. The engine has developed a slight knock ..... I have a very bad sickness...... and now that Im retired its getting worse. Yes ..... I save unwanted tractors and bring them back to life. Im right in the middle of painting my newest acquisition. So this guy will be on the back burner. Share this post Link to post Share on other sites
pfrederi 17,969 #18 Posted October 1, 2021 Sorry abut your health issues.. Best to leave it alone until you can open it up not risking further damage. Share this post Link to post Share on other sites
acc7484 52 #19 Posted October 1, 2021 Let me re phrase that .... I have a very bad sickness...... Yes ..... I save unwanted tractors and bring them back to life. and now that Im retired its getting worse. 2 1 Share this post Link to post Share on other sites
Gregor 4,847 #20 Posted October 1, 2021 (edited) 45 minutes ago, acc7484 said: Let me re phrase that .... I have a very bad sickness...... Yes ..... I save unwanted tractors and bring them back to life. and now that Im retired its getting worse. I get it now ! Most of us are a bit tetched in the head Edited October 1, 2021 by Gregor Share this post Link to post Share on other sites
acc7484 52 #21 Posted October 1, 2021 My Horses......... My New Ford LGT-16D 3-cyl Diesel 2 Share this post Link to post Share on other sites
Gregor 4,847 #22 Posted October 1, 2021 (edited) Is the 312-8 the onlt MV-12 you have? Or MV for that matter? Edited October 1, 2021 by Gregor Share this post Link to post Share on other sites
acc7484 52 #23 Posted October 1, 2021 I have another. I just brought it home from storage Share this post Link to post Share on other sites
Gregor 4,847 #24 Posted October 1, 2021 9 minutes ago, acc7484 said: I have another. I just brought it home from storage Then you should be able to compare tractors, and confirm all parts and pieces are as they should be. If everything looks good, and you are SURE the governor shaft will not spin around freely, then it's not looking good for the governor gear and weights, but like I said, I am not familiar with the M. Share this post Link to post Share on other sites
acc7484 52 #25 Posted October 1, 2021 (edited) Yes , I just compared the two. I adjusted the other tractor and the governor works as it should. From the outside everything looks the same. As soon as I get the LGT-16D painted Ill start on the WH engine teardown. Where is the best place to get quality parts? Edited October 1, 2021 by acc7484 Share this post Link to post Share on other sites
