12 hp Kohler smoking

[moe1965 743]

I have a new to me wheel horse 312b I have been working on lately  it starts good and seamed to run ok except it blows blue smoke when I throttle it up .  It doesn't smoke when I idle down or while its running.    Any thoughts.  .  Thanks 

[Maxwell-8 4,277]

Maybe do a compressions check, but definitly sound like some worn rings

[moe1965 743]

I just pulled the dip stick while it was running  and there seams to be quite a bit of blow back from the dipstick tube.  

[moe1965 743]

I took breather cover and its loaded with oil.   Sound like a new piston and rings or might something else cause this?

[Gregor 4,846]

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.

[moe1965 743]

I have rebuilt a  kohler before with my dad when I was very young and am up for the task but I'm just trying to figure out if this engine is in need of that or am I missing something simple as to why its acting the way it is.  As always all your input is very valuable and  appreciated.  Thanks

[Achto 27,609]

Severe blow by is most commonly caused by bad rings. A compression test will tell you if you have low compression but will not explain why. If you can do a leak down test, that would let you know where the leakage is.

Edited December 3, 2021 by Achto

[Gregor 4,846]

2 hours ago, Maxwell-8 said:

Maybe do a compressions check, but definitly sound like some worn rings

I honestly don't remember if a 12 HP has ACR or not. I think so.

You could perform leak down test. If it has ACR, I don't know of any other way to check piston and rings, without tearing it down.

 

 

 

 

[moe1965 743]

I guess I'm confused if it had bad rings and piston issues etc why does it start up with no issues.  If it had low compression it would be harder to get started.   I'll do a compression test on it and see what I get.  

[Gregor 4,846]

I guess if it has ACR you really can't do a leak down test either. I been up too long.

[953 nut 55,325]

2 minutes ago, Gregor said:

I guess if it has ACR you really can't do a leak down test either. I been up too long.

The ACR opens the exhaust valve momentarily just before TDC. You can do a leak-down test just past TDC.  The keyway on the crank shaft will be at the top when the piston is at TDC.

[Achto 27,609]

14 minutes ago, moe1965 said:

I guess I'm confused if it had bad rings and piston issues etc why does it start up with no issues.  If it had low compression it would be harder to get started. 

 

it may or may not start hard. I have one tractor that smokes, run a 50/50 mix of 30wt and Lucas oil treatment to keep the smoke down. Also one of the easiest tractors to get started.

Edited December 3, 2021 by Achto

[Gregor 4,846]

I am totally confusing myself. I did a leak down test on my K341.  I am going to bed.

 

[oliver2-44 9,764]

5 hours ago, moe1965 said:

I took breather cover and its loaded with oil.   Sound like a new piston and rings or might something else cause this?

This area should have some oil in it to lube the tappets. That little hole is the oil drain and it is raised off the bottom a little so it will hold oil.  

You cannot do a compression test on a kohler k or magnum due to the compression release.  

Ideally a  leak down test is the thing to do. See if your auto parts store has a leak down tester they loan out.  

PS I usually think of blue smoke only on startup as possible being due to valve guides.  Worn piston rings/oil rings will smoke all the time.

 

How does the motor run does it seem to have good power or low on power?

 

Gregor types faster.

Edited December 3, 2021 by oliver2-44

[moe1965 743]

Seams to have good power.  I'm going to clean breather assembly the Reid appeared to be stuck but I'm not sure. I'll check the exhaust and intake for proper clearance and restart.   If that doesn't change anything I'll pull the head and go from there.  

[ri702bill 8,350]

13 hours ago, Gregor said:

At the time I thought this was kind-a high

Still is, to me. I realize that time and talent is money - could have bought another complete problem free tractor for that ....

Bill

[peter lena 8,639]

@moe1965 just a question , what does the oil look like ? was this oil regularly changed ? , while I  am pretty sure that there is a wear factor involved , my initial run in with used engines was similar . usually running it in to verify operation on a separate gallon  of heavily treated gas , heat up , dump hot oil . refill with a varnish cutting additive , fresh oil , more run time , carb cleaning , tuning detail . engine running much better , idle time , fast idle time , no more smoke . cold start no smoke , ran engine for more engine cleaning time , oil change , like black coal oil . fresh oil , varnish cleaner . just a regular baseline run in for me on a engine run status .  more often than not  , this ring cleaning varnish  flush , has brought back an engine , just my experience , and my two cents , pete

[Gregor 4,846]

32 minutes ago, ri702bill said:

Still is, to me. I realize that time and talent is money - could have bought another complete problem free tractor for that ....

Bill

That's true, but this tractor belonged to my Father In Law. He bought in new in '75 (I think).  It's kind of a family heirloom. My daughter has already laid claim to it when the time comes.

[953 nut 55,325]

25 minutes ago, peter lena said:

refill with a varnish cutting additive

While working at a service station in the mid '60s we had a customer who was told his engine was "varnished up" so he went to the paint store and bought a quart of Varnish Remover which he added to the engine! After a day of operation that thing rattled banged and stunk. He brought it in and we drained the oil, it came out in chunks and had some strings of goop in it. What a mess. Out of curiosity we dropped the oil pan and there was crap clinging to everything.

My point here is that when you recommend "refill with a varnish cutting additive" you may want to be a bit more specific.

[ri702bill 8,350]

7 minutes ago, Gregor said:

It's kind of a family heirloom

I can relate to that - still have Dad's 702 her bought used in 1965.

My son has a friend that dumped a huge amount of money into a 10 HP Briggs Wheel Horse - it was his recently deceased Dad's ...

[ri702bill 8,350]

1 hour ago, peter lena said:

this ring cleaning varnish  flush

@peter lena Growing up as a teenager, I had a friend in the old neighborhood -his Dad used to buy and flip cars on the side. "Motor Medic" comes to mind - came in a half gallon can, clear liquid with the viscosity of gasoline - drain some oil out, and add this stuff, run it for 5 minutes and drain it. We used to see which of us was going to be the unlucky one to remove the drain plug.....stand back!!! Change the filter, add fresh oil, repeat oil change & filter a week later. (thicker viscosity oil to help mask the new ticking sounds.........)

I DO recall seeing bits of broken nylon camshaft gear teeth come out on mid 60's Chevys - nylon overmolded on to an aluminum hub. That was when I learned how to replace timing chains ....

Edited December 3, 2021 by ri702bill

[peter lena 8,639]

@953but@moe1965 just a question , what does the oil look like ? was this oil regularly changed ? , while I  am pretty sure that there is a wear factor involved , my initial run in with used engines was similar . usually running it in to verify operation on a separate gallon  of heavily treated gas , heat up , dump hot oil . refill with a varnish cutting additive , fresh oil , more run time , carb cleaning , tuning detail . engine running much better , idle time , fast idle time , no more smoke . cold start no smoke , ran engine for more engine cleaning time , oil change , like black coal oil . fresh oil , varnish cleaner . just a regular baseline run in for me on a engine run status .  more often than not  , this ring cleaning varnish  flush , has brought back an engine , just my experience , and my two cents , pete

[peter lena 8,639]

 @953 nut  don,t have any 1960,s varnish cleaner on hand , but regularly use rislone lubrication products , designed to work with engines .   seams like anything i say , there is a complaint about it , time to just watch things burn down ,  let it be, pete 

[moe1965 743]

Not sure the history on oil changes of this engine but before I attempted to start it I drained the oil it was very black and dirty. I only ran it for about a half hr yesterday hoping it would clear itself out.  Today I'm gona re assemble the breather I think that it was stuck and not operating correctly I'll keep you all informed

[moe1965 743]

What a mess.   Something is not quite right.