12 hp Kohler smoking

[Gregor 4,846]

Bearing plate gasket or seal appears to be just about gone.

[jtrosp1980 89]

It could  e multiple problems sounds like rings are worn valves could use a seat job and might be a blown head gasket that is seeping until under a load just my two cents

[moe1965 743]

Sorry to keep asking questions but I'm baffled  I know there us a lot of debate on doing a compression test on these kohler engines.   Here is my latest finding and confusion.   I put a pressure gauge on and it jumped up to 75 psi.  Just for the heck of it I put the gage on my c141 which runs and starts no smoke and runs awesome and I only got about 40 psi.  I'm assuming that the compression releas is working properly on the c141.  So could the compression releas on the 312 b be stuck closed giving me my issues   If so where is it located in the engine and how to check it.  I'm still blown away on how good it starts and runs but is still pushing smoke on throttle up only. I'm going to pull the head off it today and see what I find inside and go from there.  I'm thinking at this point I have tried all the easy stuff I know and it's time for a heart transplant .   

[pfrederi 17,741]

Either do a leak down test or look at the engine test in the older K series service manual  You can check your ACR just look at the exhaust valve behind the breather as you crank it should open wide exhaust stroke and just a slight bump on compression stroke

 

 

Edited December 4, 2021 by pfrederi

[squonk 41,161]

 

   Not only did that engine run hot, but the internal pressure probably blew every seal and gasket in there. Either find another engine or take $10 worth of quarters to the car wash degrease and overhaul. She's whipped! 

[Howie 886]

Yah,that thing probably been pretty warm. Bet the rings don't have much tension left in them.

[RED-Z06 2,221]

On 12/2/2021 at 5:43 PM, Gregor said:

I once had a 14 hp Kohler I had to jamb the dipstick under the starter, or it would blow out. It didn't really smoke much that I remember. It got rebuilt. This was 2017. I knew nothing about engines, even less than I do now. I had the local guy rebuild it for me. I told him to give it the works. If he could get a new part, do it. He did. Even replacing the little rubber grommet in the points cover. He took the block to a machine shop to get checked. They cleaned it, bored it, replaced the valve guides, and lapped in the valves.

At the time I thought this was kind-a high. I still do, but he only did what I told him to do, so I can't blame him. Since about this time last year I have rebuilt a 7 HP Tecky, 7 HP Kohler, (2) 8HP Kohlers, 12 HP Kohler, (2) 14 HP kohlers, and a 16 HP Kohler Twin. I don't have half that much money in any of them. Of course, I did have to spend a couple bucks on tools. Some I needed, some I just wanted. If a motor can possibly be saved, I save it. Have not found one yet that couldn't be. Although that little Tecky almost got the better of me, But I won.

In 2005 i rebuilt a M10S on a 310-8, .030+ bore, piston, rod, rings, gov shaft, carb kit, fuel pump, gaskets/seals, and machine work on the block i was in it 650..and then about 6hrs...since then ive rebuilt hundreds of engines and only a couple times spent that kind of money on parts for one. Kohler k/m engines can just get expensive.

[RED-Z06 2,221]

On 12/3/2021 at 4:34 PM, moe1965 said:

What a mess.   Something is not quite right. 

Looks like a classic blown head gasket that has been used for a long time.

[953 nut 55,325]

On 12/4/2021 at 1:54 PM, moe1965 said:

I put a pressure gauge on and it jumped up to 75 psi.  Just for the heck of it I put the gage on my c141 which runs and starts no smoke and runs awesome and I only got about 40 psi.  I'm assuming that the compression releas is working properly on the c141.  So could the compression releas on the 312 b be stuck closed giving me my issues

The compression test can be done on an engine with ACR by backing off the valve lash to the point where the exhaust valve won't be lifted by the ACR cam. It could be the exhaust valve lash on the 312 is not set properly. Considering the other problems under engine tins I don't think you need to worry about that until you have corrected the condition causing the gunk build up on the cooling fins.

[moe1965 743]

I took the head off and found a few scores in the cylindar wall I have a friend that owns a machine shop and he us going to hone out the groves and get a inside measurement and see if we can ring it or if he will have to replace with a oversized piston. Also all seals are going to get replaced.

[RED-Z06 2,221]

Bore looks good, youll have vertical marks, if your fingernail doesn't hang up on them they are probably superficial, if I had to wager a guess id say maybe a bad oil ring, but i dont see anything there besides bad seals and gaskets to indicate a big issue

Edited December 7, 2021 by RED-Z06