fish59 0 #1 Posted April 27 I have a 312-8, 1996, with the Kohler M12S. It doesn't lose or burn oil, but the compression is low judging by the fact that when I shut the engine off it keeps spinning for a while as if it has a very heavy flywheel, which is what I thought it was. In order to make the engine last as long as possible what oil or additives do you more experienced people recommend? Thanks in advance for your time. 1 Share this post Link to post Share on other sites
elcamino/wheelhorse 9,082 #2 Posted April 27 I used shell Rotella 30 weight year round. Use it in my 1972 8hp k191 , 1986 310-8 and 1987 416-8. It is sold my Advance auto by the gallon. It the motor or the PTO that spins. 3 Share this post Link to post Share on other sites
fish59 0 #3 Posted April 27 Thank you, Jim. Anything short of an overhaul I can do about the weak compression, or is it not a concern? I am in Yorktown and I use my Wheelhorse for a small veggie growing business. If I ever need work done on it, is there someone you can recommend? I also have an 8-25 I'd like to get going. Thanks again for your time. Rick Share this post Link to post Share on other sites
SylvanLakeWH 24,251 #4 Posted April 27 1 hour ago, elcamino/wheelhorse said: I used shell Rotella 30 weight year round. 2 Share this post Link to post Share on other sites
lynnmor 6,837 #5 Posted April 27 Check the valve clearance, or better yet do a complete valve job. 1 Share this post Link to post Share on other sites
elcamino/wheelhorse 9,082 #7 Posted April 27 Try @richmondred01 He rebuilds Kohler engines , does a great job . He is near me . 1 Share this post Link to post Share on other sites
richmondred01 2,209 #8 Posted April 27 Sounds like time for a rebuild. No such thing as mechanic in a can. Get it over to me and I’ll rebuild it. 3 Share this post Link to post Share on other sites
Brockport Bill 1,404 #9 Posted April 28 Kohler has their own label oil they engineered with zinc additive specifically for their older engines. Share this post Link to post Share on other sites
Wild Bill 633 773 #10 Posted April 28 10 hours ago, Brockport Bill said: Kohler has their own label oil they engineered with zinc additive specifically for their older engines. Made by Amsoil, Share this post Link to post Share on other sites
rmaynard 14,934 #11 Posted April 28 13 hours ago, richmondred01 said: Get it over to me and I’ll rebuild it. And he will do a great job! Share this post Link to post Share on other sites
richmondred01 2,209 #12 Posted April 28 49 minutes ago, rmaynard said: And he will do a great job! Thanks Share this post Link to post Share on other sites
Fordiesel69 228 #13 Posted April 28 That's not a symptom of low compression. They have a compression release on the cam. If it doesnt knock, or burn oil, run it. Monitor air cleaner and the little blowby hose going into the air filter housing as well as play on the throttle shaft. Those issues will fast track you quickly into needing a rebulkdd Share this post Link to post Share on other sites
fish59 0 #15 Posted April 29 Thanks to all of you. This is really helping. Can someone please elaborate on Fordiesel's comment about watching the play in the throttle shaft? Not sure exactly what that is, is it on the carb and what's the fix if its loose? Share this post Link to post Share on other sites
Fordiesel69 228 #16 Posted April 29 The play in the throttle shaft is a thing you will see mostly on single cylinder engines. It can happen on others but not as often. What happens is the pulses back and forth from the compression, move the throttle shaft back and forth and over time this will egg shape out the hole in the top of the carburetor casting. The shaft will then be "sloppy" instead of tight. The early symptoms are not very severe and this is when some of the dirt will start to be sucked in. Once it gets loose, it will wear much faster and eventually lead to a carburetor that is impossible to tune / adjust. If you keep running it, the increase in dirt coupled be periodic lean mixtures will destroy the top end of the engine. It has been known to wipe out the rings, it will micro polish the cylinder so it will look like chrome (not a good thing), and also has been known to warp the cylinder head on 14 and 16 hp engines. I am replacing a carburetor on a K301 soon and I will make a video. It is very bad and I do not have machine shops in my town that can handle this repair. Share this post Link to post Share on other sites
lynnmor 6,837 #17 Posted April 30 Here is a good video that spells out a number of things about ZDDP and adding (in my words) snake oil. It gives you an idea of why I recommend oil be the only thing in your crankcase, just buy what was developed for your application. The level of ZDDP has been mandated, by the powers that be, for engines with catalytic converters and does not apply to our needs. Oils that are produced for our simple engines and labeled as such gets around those mandates. But yes, I know that I am beating a dead horse here. Share this post Link to post Share on other sites
Mark siebenaler 41 #18 Posted April 30 On 4/27/2024 at 3:26 PM, lynnmor said: Check the valve clearance, or better yet do a complete valve job. Exactly I always do it when I get one Share this post Link to post Share on other sites
