bo dawg 516 #1 Posted November 10, 2020 I have a 12 hp Kohler head gasket leaking, but it also smokes alot when running. Someone told me to change the gasket before installing new rings that it might be just the gasket causing it. Is this possible or is it still bad rings? Share this post Link to post Share on other sites
rjg854 11,691 #2 Posted November 10, 2020 Once you remove the head, you'll know a lot more. It's hard to speculate, without investigation. 3 Share this post Link to post Share on other sites
953 nut 56,642 #3 Posted November 10, 2020 It is unlikely that a bad head gasket will result in oil burning. The replacement is an opportunity to take a look at the condition of the cylinder. 3 Share this post Link to post Share on other sites
The Tuul Crib 7,338 #4 Posted November 10, 2020 10 minutes ago, 953 nut said: It is unlikely that a bad head gasket will result in oil burning. The replacement is an opportunity to take a look at the condition of the cylinder. Share this post Link to post Share on other sites
pacer 3,174 #5 Posted November 10, 2020 As others said, the gasket leak is not gonna be the cause of the smoking. You've just got a tired old Kohler, as tough as they are they do eventually wear. If youre really lucky .... you might get by with throwing a new piston/rings at it ---- but probably needs some heart surgery. Heres the kicker, ---- you need to do it NOW! If you keep delaying it may come apart. and then youve just got a boat anchor! Really should be taken apart and you, or some one, do a good inspection of all the internals. Along with probably needing a bore job/crank turn, the valves need checked and very likely get rid of the "grenade gears" (balance gears) Youll thank your self by getting this done before disaster strikes --- and, youll have a like new engine! 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,376 #6 Posted November 10, 2020 Could be valve adjustment and or burnt valve... Share this post Link to post Share on other sites
bo dawg 516 #7 Posted November 10, 2020 7 hours ago, 953 nut said: It is unlikely that a bad head gasket will result in oil burning. The replacement is an opportunity to take a look at the condition of the cylinder. Thats what I thought. If oil is already getting up there its at least the rings if not not more. 1 Share this post Link to post Share on other sites
richmondred01 2,280 #8 Posted November 10, 2020 Check the Valve guides too. 1 Share this post Link to post Share on other sites
bo dawg 516 #9 Posted November 11, 2020 The hard part for me is I really dont know what Im looking for. Never got inside an engine before. If it aint broke then I wouldnt know what im looking at. Lol Share this post Link to post Share on other sites
WVHillbilly520H 10,376 #10 Posted November 11, 2020 Burnt valve pics below... They are videos on youtube that show you how to check and adjust the valves lash... Head gasket will have black/dark spots on the inner sealing ring where if its leaking, the piston shouldn't rock within the bore. 2 Share this post Link to post Share on other sites
richmondred01 2,280 #11 Posted November 11, 2020 (edited) In the end you want it to look like this. You should try to find someone in your area with experience working on these engines. It may be a bit of a challenge because I’m finding no shops that work on the old flatheads. That knowledge is fading. Look in the member section and see if there a member close by that may at least oversee what you are doing. Most important is finding a quality machinist. Edited November 11, 2020 by richmondred01 1 Share this post Link to post Share on other sites
Rob R 970 #12 Posted November 11, 2020 Agree with all comments here.... take you hand and place it on top of the piston and move it side to side if you have piston slap time for a re-build..... me thinks.... 1 Share this post Link to post Share on other sites
WVHillbilly520H 10,376 #13 Posted November 11, 2020 (edited) After cleaning finding another valve and a little hand lapping the "seal" on my valves is back, they held light (10w) oil for 24 hours... Crazy that a 12hp issue was brought up as I was working on this 12hp Cub. Edited November 11, 2020 by WVHillbilly520H 2 Share this post Link to post Share on other sites
bo dawg 516 #14 Posted November 11, 2020 Heres what I'm looking at. I plan on popping off the head cover this weekend hopefully. More than likely wont go as far as you guys would, Im not gonna spend the money on a mechanic/machine shop. I didnt pay much for the this 120 and the Bronco 14 I took in. I was just interested in the loader this 120 had on it. So if it isnt an easy fix I'll just sell it or scrap it. Bad thing is this motor runs and starts great, just smokes like a freight train. But since I really have never tore into an engine I thought it might be a good donor to learn something. Share this post Link to post Share on other sites
WVHillbilly520H 10,376 #15 Posted November 11, 2020 @bo dawg, second picture definitely looks like a leaking head gasket and if the rings are worn or a valve is burnt like mine above it can pull oil up the valve stem or past the rings and into the combustion chamber then on out the head gasket as well the exhaust... But it really isn't that hard to check the valve lash and once the head is off the valve face/seat condition can be checked with a mirror and light. 1 Share this post Link to post Share on other sites
