Kohler command 14HP smoking. Filled engine with fuel, good compression

[bob112]

I am an engine guy but debating how far to go. Bought an otherwise good mower for a friend as not running. I noted the carb stuck and filling engine with fuel. Of course I changed oil and fixed carb. I have not done another oil change yet because I am debating if I should waste more coin on it.

Pumping up about 170psi compression, engine sounds really good other than low speed jet seems to be still plugged or is not drawing fuel properly. Not running right at idle at all! When engine is loaded, it hits fine BUT smokes like a freight train! This engine has hydro lifters. Plug is super lean!

Just wondering if anyone has run into this? I was going to throw 30sae oil in as it will only be used in warm weather. No sense if engine is toast. Was going to do a leak down on engine but figured I would post first.

The load causing more smoke to me means it is bypassing the rings but maybe some plugged crankcase breather?

 

[CalG]

170# compression is not indicative of bad rings or failed pistons.

Smoking under load? Valve seals? What does it do when you back off?

With compression like that, I would say an oil change is small money to find out.

 

[Walt 2002]

I bought a 14 hp Kohler Command, CV14, several years ago. Sometimes it would smoke so badly I was embarrassed to be seen in the yard with it. I got new rings, gaskets and seals to rebuild it but the engine used very little oil and only smoked for maybe 30 seconds when first started and just sometimes. The parts are still lying in the parts cabinet where they have been for about 10 years. I have been thinking I should use them before I get too old to do the job.

Walt Conner

 

[bob112]

Changed oil to 30wt and filter. Mower did not smoke a lick for about 5min while I thrashed around on it. Then it started smoking. Probably not as bad as before but bad enough I would never leave it like this.

The higher the load, the more smoke you get. near idle, it is a faint blue trail but put to coal to it doing doughnuts and you will even get smoke rings out the exhaust.

I am wondering a bit about the mechanical fuel pump. Heard there was some issue with them leaking back into the engine. This is the second oil change in 15min of running so I would usually have the gas cleared out of the case by now. If I still have fuel in it, this could be something.

Other thoughts? Engine seems to run like a top otherwise. Low speed jet is still off so I need to clean the carb again but no biggy there. Smoke is the kicker...

 

[CalG]

Changed oil to 30wt and filter. Mower did not smoke a lick for about 5min while I thrashed around on it. Then it started smoking. Probably not as bad as before but bad enough I would never leave it like this.

The higher the load, the more smoke you get. near idle, it is a faint blue trail but put to coal to it doing doughnuts and you will even get smoke rings out the exhaust.

I am wondering a bit about the mechanical fuel pump. Heard there was some issue with them leaking back into the engine. This is the second oil change in 15min of running so I would usually have the gas cleared out of the case by now. If I still have fuel in it, this could be something.

Other thoughts? Engine seems to run like a top otherwise. Low speed jet is still off so I need to clean the carb again but no biggy there. Smoke is the kicker...

Is the crank case oil level above the full line?

If fuel were entering into the crank case and both diluting the oil and raising the sump level, Smoking would be expected. This would be consistent with the "5 minutes of no smoke". That you describe.

 

[bob112]

No, I just checked it. I was not super precise when filling as I sort of expected this so I cannot verify if the level went up or not but it is right at full.

Because the engine otherwise seems to be in good shape, I want to find the source of the oil burning. Guess the good part is this is an OHV, pushrod, air cooled engine so maybe looking at the valve seals will be easy? I have the tools and probably the parts but I simply hate doing repairs on a whim...

I know engine was full of gasoline. It holds about 1.2qts but I took 1.5gal out of it! Previous owner ignored the faulty fuel valve so it would continuously fill due to a dirty needle/seat.

 

[buickanddeere]

Repair the carb to prevent the lean operation problem and get back to us. Is the smoke from burning oil or burning excess fuel? Is the engine being operated at full rated Rpms ?

 

[bob112]

I worked on the carb more but will have to bite it and pop out the welch plug that covers the low speed ports. still not quite right.

HOWEVER, I ran it hard for 15min and smoke is all but gone! Having to work out all the crap in the muffler and such I guess. Ran it out of fuel so I guess it is a sign to pull the carb again and do it right. GD little idle passage is all but impossible to get to. When fully loaded, it hits fine so main circuit is working but probably still lean due to low speed circuit not being right.

So I think we got er!

Oh, smoke was certainly oil burn. Know it well..

 

[bob112]

Spoke too soon.... Seems I have the smoke issue licked but I cannot figure out this rough running at lower power. The engine stutters but will always keep going. This occurs at idle all the way to full rpm. Only when the engine gets loaded will it stop doing it. I can nearly guarantee the carb is 100% good to go having pulled everything on it and triple verified all passages are clear and moving fuel.

This IMO is somehow pointing me to an ignition issue. I usually see the governor dance around when they are not getting fuel but this one is solid. Of course a new plug. I have an inductive series light I can put on the plug wire but if it turns out positive for missing, what the heck am I looking for? air gap or coil is about it, right? Unless the coil is getting grounded somehow? Engine does have an oil pressure switch but no clue where it is going because there is no indicator light.

 

[bob112]

Ah, head gasket is blown. Prob would not have caught it without looking at the ignition coil. It was testing up fine but as I turned engine by hand, I could hear it. Must be just a small enough leak to pull air at lower carb settings and not affect things as much at full WOT. Also compression tested good. Should have done the leak down test.... Chased a carb issue for nothing.... Tis life. I will throw a gasket at it and should fix me up.

Only question I might have is, do I have to drain my brand new oil for this? Guess I can try to estimate with the dipstick I suppose.