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Kohler 25 smokes

2971 Views 29 Replies 16 Participants Last post by  blairbuc
stated brand new, did the 5 hour oil change, went to Amsoil Synthetic and kept using the synthetic from 5 hours to 67 hours.

Just in case the synthetic kept it from breaking in , it drained it today and went back to dino oil in hopes the rings just need seating , but synthetic of no synthetic, its been 67 hours and a light white smoke still comes out the exaust. Better seen in bright sun light, not that obvious but I can always smell it.

Thougth it might be running rich with a dirty air filter, changed it today and it made no difference.

I notice if I back off the throttle it gives a one second puff of smoke which should signify something but I can't remember if it mean a bad valve guide or not.

Any ideas, head gasget, bad gas, unseated rings, exaust recycle doo-hicky, what causes a light constant stream of white smoke out the exaust that gives one puff when you back off the throttle or is this normal for Kohler?
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It's not normal for Kohler engines to do this. It could be caused by several things. At 67 hours take it back to the dealer and let him worry about it.
I have never noticed a Kohler to do this. In fact to this date I feel that Kohlers are one of the easiest, and best running engines that I have ever used. Nice & Smooth
Since it is white smoke at least it is not oil burning. Sounds like you are seeing whats left of burning gas. Ours will do that if you work them hard. If it was water cooled I would say that there would be a possibly of a head gasket leaking.
The P.O.S. 1998 model of the 25 I had did the same thing at about 100 hours out of the box. It was the first of many defects in that motor. Mine was a scored cylinder and there was no abuse or dirt injestion. There was no explanation and it never was a good motor for me.
Good Luck.
I'm with MOW ED on this one. Gonna take a lot to get me back on a Kohler. Sounds like it could be a head gasket. Mine sounded like a VW bug and smoked a LOT! Never had original power after the gaskets were done, and they were done twice. Then the smart spark, twice. UGGH!

Very bad taste in my mouth with Kohler. Then when I find out that MOST 25's did this :eek: That just p!ssed me off even more!

I really thought Kohler had that mess straightened out by Y2K, but....

DO NOT MENTION AMSOIL to the dealer. Kohler gets wind of that and they'll run a mile with it.
How much is it using? I never recommend going to asynthetic until after 100 hours of good hard running to seat the rings in. Synthetic oil is great stuff. Super slippery. That's the way it's supposed to be. The internals of the Kohler engine aren't designed to have the super slippery stuff in right fromthe beginning. If they were, it would have it from new. If no oil usage is detected, run it hard with the petroleum based oil and see if the problem goes away. If oil consumption is a problem, get it to a dealer ASAP.
Jman and the rest, thanks for the replys.

does not seem to be an oil burner, but I was not real keen on detecting small usage, just keeping it above line and not paying attention to quanty over hours. I drained the synthetic and put dino castrol 10w-30, gave it a new air filter, sucked out the gas and tried a different station with fresh. No change, hardly any smoke while warming up and then 15 min later it starts the small steady stream and the one second puffs it I back or or apply throttle.

Called Kohler, they want three tests done, Compression, leakdown and some pulse test which I think judges pressure coming from the crank case.

In general they feel it could be something to do with a one way valve that I think is part of the emissions. Head gasket was brought up too.

I will say one thing, the dealer said Kawi was not free of there problems either. Maybe I'll try one next time, but the Kohler guy were nice, did not jerk me around, communicated well ect.

Actually two different mechanics pushed me into Kohler over Kawi based on general issues. Thing is, besides Lesco's stupid air foil set up, I don't hear to many Kawi Horror stories. I know Kohler had a lifter problem that was fixed prior to my engine, I ordered the serial number to miss that one. I hope its a small issue, I still like the motor and notice not power loss.

Getting back to the Kawi 23 which was my other choice on the Hustler mower, the mechanic said in the Kawi shop manual , Kawi wanted heads pulled every 350 hours to get carbon out. Seemed strange to me because there our guys on this forum with 2000 plus hours on their Kawi's without head pulled. Live and learn.
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Kohler Tec guy said the light annoying smoke comes from a failed primary and or secondary breather valve. Nothing serious, no real oil consumption and no harm to engine. It would run for years with this condition without harm. They are pulling the head and changing breather valves.

The Kohler guys were good about it and made sure they kept a customer, no jerking me around. The head tec guy said they knew Kawi took a lot of the market about 5 years ago when Kohler heads were blowing gaskets and they are not looking to go back there. He said the Kohler Command's major issues were worked out years ago when I asked him is there anything I should switch out since the motor was going into the shop. We'll see. I told him thank, we talke for 20 min. and I told him I can't even get a true Kawi Tec on the line for my other engine. Its not back yet but so far I liked dealing with Kohler. My dealer said even if this was out of warrante they are good about taking care of customers as long as you don't do something stupid.
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, just keeping it above line

kohlers seem to do best just below the line.
I noticed the just above line comment as well.

That line is there for a reason. DO NOT take it over the line. Bet that will make a difference. I like to keep mine a couple hairs under the line. Also make sure your engine has cooled and the engine is perfectly level before checking the oil level.
Once you get the engine back please let us know what it ended up being and if everything was fixed properly. Sounds like the Kohler people are at least treating you well.

Gravely Man

So far the dealer has pulled both heads.

The Pistons are tight, walls are fine, valve guids tight and no head gasget leaks. The mechanic is not familiar with the primary or secondary breather valves on each cylinder bank but a Kohler Tec told me he would call the mechanic and guide him. He said they are simple 50 cent items to remove and replace and simple to do. Even the valve adjustment on the Kohler is close to fail proof. I asked this third mechanic how the Kawi's were doing and he, like the other two said he prefers the new Kohlers in the big engines and the Kawi's in the small stuff. By small I assume he meant non twin engines. Said he has carb problems with the Kawi. and more coil issues. He also said there is a 350 hour head pull off and scrape carbon procedure on the Kawi twins . I laughed and said, if you follow Kawi's rule, you will never have a head gasket problem if you are replacing them every 350 hours. He did say his customers ignor the rule but it was curious why Kawi would design a head that would collect carbon. As far as getting a Kawi tec on the phone, he said he can do it but I told him for an outsider I still can only get a distriburter and like Kohler's Distributer there was no one to talk shop with. When I called Kohler Tec. they will talk shop all you want and they really did . per my request, call the mechanic and walk him thru the breather valves. I can only assume the dealers unawareness to the breather valves is because they have never had to do one.. Either that or I have a bad mechanic tinkering with my unit.

I find out the outcome tomarow but so far the real guts of the engine show no failure, all indications are towards the breather valves and not the head gasgets, which was a popular guess on this site. Kohler said that problem is almost gone on the newer commands.
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Originally posted by blairbuc
Said he has carb problems with the Kawi. and more coil issues.
Yea i know all about that. Just sent my mower in the shop with the 17hp kawi. and have to replace both coils in it with 234 hrs on it and just out of warranty.
Originally posted by TLS
...Then the smart spark, twice. UGGH!..
Whats that?
lawn boy

one thing you have to remember. there are Kawi and Kohler lovers. My gut tells me these engines are close competition with different little quirks that both companies are weeding out. Chances are Kawi has taken enough beating with that suppliers of coils and the ones you are getting have probably been updated. Just like Kohlers update on head design.
Gravelyman and the rest

The kohler 25 came home yesterday.

The small but annoying white smoke is gone.

Mechanic said he changed the primary and secondary breather valves but also noticed a small amount of oil getting past the rings on one cylinder, so he figured the rings did not seat for some reason.

I will never know if the white smoke was me using Amsoil too soon, and not lettiing that ring seat or if it was the breather valves. Turned out, the head gasgets were not the issue.

At this point he said the amount of oil getting past the ring was very small.

My guess is , some guys say you can add snythetic in 10 hours, my opinion is I will wait somewhere in the neighbor hood of 100 to 200 hours before I go synthetic. This may not have been a Kohler problem.

Kohler beefed the heads up sometime in the later 90's so the head gasket issue may be long gone for the bulk of engines out there. Another thing they do now is to send out studs and nuts with the head gaskets. Kohler does not want you to use the older style big head bolts. Torquing a large bolt is less succesful than applying torque to a nut on a stud already in the engine block. The nut has less surface contact than a big bolt , so the torque setting is more accurate. Another issue with with the old style head bolts were that they were stretch bolts so if a bad mechanic re used the stretch bolt you would have a head problem sooner than later.

Bottom line, go studs and nuts for the next head gasget job and toss the stretch bolts.. My engine was a 2001 and came with the studs and nuts.

Kohler said they would cover an issue I had past warrenty over this repair. It was 6 hours x $70 for Kohler bill.

I'm not ready to go Kawi yet and then again this is the third mechanic I have talked to who seems to edge more towards Kohler but seems like its a close call with him on this one. The other two were definate Kohler fans. He said now we are getting in big Honda's on the commercial stuff. So far he said what they have sold has not come back.

At the end of day, the Kohler people were not sleazy and easy to deal with. I
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All I can say about my Kawi 23 is that it is about to hit 1400 hrs and has never had a problem. None. The front crankshaft seal is starting to seep just a tiny bit... but right now it amounts to less than a teaspoon a week. I plan on changing both front and rear seals (and the original wagner electric clutch) at the end of this season. :D

Ive got another mower with a Kohler Command 16 with close to 1000 hours and it has performed flawlessly too. :D

well, your a proven track record.

you do anytinig special or just use dino oil and change often.
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