What killed my Kohler?

[HankB 16]

WOW!! I have never given that any thought. I often let the thing set around and go "Putt Putt'. I even drive around pulling grandchild at VERY low idle.

Guess I'll have to crank it up a bit.

There are two good reasons not to operate at low RPM.

1) Oil doesn't get splashed around as much.

2) Cooling air flow is reduced.

If you operate under load at low RPM, then you will increase bearing loads as well. (OK, three things.)

[shorts 182]

broken rods are not totally unheard of in Kohler K engines, the question becomes why? if it was a structural or mechanical failure of the rod, the rod would have broke and their would be no deposit of aluminum on the crank, so that points to a lube problem.

When their is a lube film failure the aluminum rod starts to gall and transfer material onto the crank until the friction becomes great enough to break the rod. the good news is that the crank is probably not hurt and is salvageable by gently picking the aluminum off of it and micro polishing instead of grinding or replacing it.

also look at the piston for signs of lube failure and galling, it also depends on splash oil for lubrication of the wristpin and cooling.

when I was a youngster, ND oil was recommended in air cooled engines, I think the rrecomendation changed to detergent oil when they started using pressurized oil systems and could use oil filters to help clean the oil.

[wooley12 0]

The failure was definitely from lack of lubrication. After downloading and reading the Kohler online "Failure Study Guide" it appears the dipper broke off. Strange to have that happen after so many hours. I removed the aluminum from the crank by swabbing muriatic acid on with Q-Tips. Not sure yet if I'll rebuild ($350 - $400 in parts) or part out the whole machine. I think honing the bore will make it "good enough".

Heat discoloration on the rod but not on the broken dipper

Tip of dipper dinged. When did that occur?

Fracture surface

More autopsy photo's here

https://picasaweb.google.com/wooley12/Kohle...CKTs4ZH40YmJYg#

[sorekiwi 761]

Interesting. I agree with your conclusion that the dipper fell off first, I wonder why?

Any chance there was some foreign object in the engine? I think its one of the Kohler manuals that decribes a case where part of the governor gear came off and ended up in the oil pan, where it broke the dipper off the rod.

Maybe something off one of the balance gears? I have seen pictures on here of a piece of the bearing cage out of one of the main bearings was lying squished in the bottom of the oil pan.

:hide:

[wooley12 0]

There was nothing in the bottom of the pan except the pieces belonging to the rod that obviously broke after the dipper and a few small pieces of the piston skirt. The "dings" on the dipper rod tip are suspicious. I feel worse about the demise of my Horse than when I watched my 1976 Bultaco, that I bought new, leave on a trailer with the new owner last year. The buyer said he'd bought a lot of antique motorcycles before but this was the first time he got one from the original owner. :hide:

[puddlejumper 67]

Obviously, You will probably never know for sure, But my suspicions would lay with the man that rebuilt it. Or possibly the packing house from which the new rod came. Bottom line it was dropped sometime before installation and went unnoticed or got a shrug of the shoulder and a it,ll be allright.

[wooley12 0]

Update!!- We'll, I honed out the major gouges in the cylinder wall, cleaned the aluminium off crank with acid and slapped in a new rod, piston and rings just in time to get running for the fall leaf and winter snow seasons. My neighbor helped me a bunch including using a tach to set the high speed. On listening to what the correct speed is, I realize that I'd been running it at 500 or more r.p.m. over the limit. 5 years of that could surely have led to the dipper breaking off. We'll see how long it will go at the right speed with my quick and relatively cheap fix.

[Ken B 3,189]

That is great news! I hope it lasts you another 20 yrs. I'm glad you didn't part that out, If you ever do, I got dibs on that seat!

[rmaynard 16,333]

Always glad to see a thread come to a happy conclusion. Setting the proper RPM's, both high and low, plus changing the oil on a regular basis ought to keep you going for quite a while.

My fear is that my Wheel Horses are going to outlive me. :wh:

[wh5208speed 646]

Here is Toro/Kohler's recommendation on all things oil.

Here is what I have been running for about 10 years and have had zero problems. Meets all of Toro/Kohler's requirements and it's synthetic.

Thad (Ohio) :dunno:

[can whlvr 994]

so from the all things oil its ok to use 10-30 if not using sae30?

[wh5208speed 646]

You can use either SAE 30 or 10W-30 as long as you use a API quality rating of "SH" or higher.

Thad (Ohio)

[Rooster 192]

the operators manual

these folks usually know somethin'

What manual is this from?

[Martin 2,133]

the operators manual

these folks usually know somethin'

What manual is this from?

looks like similar wording in this one except the sf and sg classification is sg and sh, so id say its one of the later variations of the kohler engine manual.