Issues with Cub 1650/kohler k341

[Terry C]

I hope this works out for you but statisticly it doesn't. Old cast iron Kohlers don't
usually don't respond well to a ring and hone job. I've only tried once and it didn't.

[Rendrog18]

If the piston was slapping why would adjusting the valves, points, and plug gap eliminate it? It was a very definitive knocking before I adjusted those three and afterwards had no knock at all. It would also spudder and hesitate and not come up on idle fast before adjusting it. All those symptoms also disappeared after the adjustments were made.

If it were piston slap wouldn't the knocking still have been happening when I used it for close to an hour?

[sawdustdad]

The fact that you have silver sludge in the crankcase is proof of piston skirt wear.That is caused by piston skirt rubbing the cylinder wall. Usually most noticeable under heavy load. Whether and under what conditions you hear it may vary. Poor timing by itself does not cause that kind of wear but a loose piston in an oval cylinder will suffer from poor timing more dramatically.

You started off this thread with "PO put new piston and rings in..." Now you are about to repeat his mistake.

What's the definition of insanity? Doing the same thing repeatedly and expecting a different outcome...

Not saying you are insane, don't take offense. Just sayin' you're in denial.

All that being said, if I were not building the machine for long term work, maybe just tooling around with a cart or something, that didn't stress the engine, you might be able to run it for a number of years with just a ring job. But to cut grass, plow, snowblow, think about the time you'll have invested and the long term payback of a fresh engine. We've all made the mistake you are contemplating.

[J-Mech]

Well, you came here with a story and asked some questions. Now your arguing with those answers.

It's a waste of time to put pistons and rings in it, but it's your money and your motor.

Yep, you probably had a spark knock and it went away.

I question your measurements because you gave them, then said you pulled the piston. You can't measure taper with the piston in the hole. Do you have a bore gauge? Inside mic? Or are you using a t-bar and a cheap caliper? If you do in fact have the measuring tools to get a good check on the bore, you are either an experienced mechanic, or a machinist. If your using questionable methods, and cheap tools, then your jerking us around with the numbers. Which is it?

Glad your dad worked for GM. How many Kohlers has he rebuilt? How many motors? Most all factory trained techs I've interviewed seldom ever saw the inside of a motor because a dealer just replaces, never rebuilds. I've rebuilt hundreds of motors, and I'm telling you your wasting your time. I have this feeling your going to argue with me too......


EDIT: More than likely, it is an aftermarket piston in standard bore. The skirt clearance was probable too tight.... and you going to try that again???

[Steve149]

[Alvy]

Originally Posted by Terry C

I hope this works out for you but statisticly it doesn't. Old cast iron Kohlers don't
usually don't respond well to a ring and hone job. I've only tried once and it didn't.

Same experience with one, did the rest the right way

[Mike McKown]

35 years ago, my boss gave me his 104 and told me he wanted it fixed. Was burning oil and low on power. Fix it cheap he said!

I got it apart and saw the piston top was eaten away almost down to the top compression ring. The bore looked good as far as wear. I didn't measure it except eyeball. New Kohler piston and a set of rings and back together. No valve job, just piston and rings.

That was 35 years ago and the thing ran for him for another three years then he sold it to me after the sediment bulb filled up with water and wouldn't run. I used it for ten years and it's basically been parked since but still running okay. No telling how many 100's of hours is on that little engine because he had a very large yard and he cut his dad's yard and his sister's yard down on the farm with that thing.

I guess you can get lucky now and then but WDIK? I'm not certified on anything!

[Yosemite Sam]

I believe what Mike says is exactly right, once in awhile you can get lucky.

I bet he feels like one in a thousand, maybe one in ten thousand...

My question to the OP is, why do you think you can do the same thing that a PO did and end up with a great machine when the PO couldn't do it?

The op asked for opinions, and mine is: Someone already tried the cheap fix first and the only person it worked out well for was the guy who "unloaded it".

Fix it right and use it, or do the same thing that someone else already tried and failed at.

The OP doesn't need to justify anything with anyone here, he asked for opinions, not debate.

[sbauerz28]

I don't feel that a rebore is needed if the cylinder is truely within spec. A bad hone job will also cause ring seating issues. I think it is false to say every engine needs to be bored to be considered rebuild properly.

I do agree that most of these engines that get torn down probably do have out of spec cylinders that need to be machined.

The statements above are only my opinion. Please don't beat me up to bad for stating it.

[Merk]

Measure the cylinder in 6 places like the Kohler manual says and report back with your findings.

You also need to post what tools you used to measure the cylinder.

One thing you need to remember when rebuilding/replacing a piston and is the cylinder will grow in diameter when you hone it. I've been a machinist for close to 40 years and saw enough poorly done rebuilds that I could write a book.

The silver sludge in the pan is another indicator that the motor needs some major work done to it. I would recommend you check the crank pin and rod journal to make sure they are in spec. Crank pin should check in 6 places per Kohler manual.

You also need to post what tools you used to measure the crank.