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Discussion Starter #1
Hi all,
I've been able to laugh at my earlier post where I showed my mental handicapp. Trying to keep a sense of humor about it all.
I had just re-installed my re-re-re-built k-321 motor from the second rebuilder guy after his first attempt failed.
he asked me to deliver the carb, coil, cooling tin and starting motor so that he could run it on the bench and satisfy himself that all was right with this latest re-rebuild. The motor was ran and the report was that all went well with none of the observed previous problems and that the motor was ready for pickup. THe motor was re-installed lastnight in the 1987 224.
After throwing it IN gear, this afternoon :p, I took it out for it's fifth maiden voyage on it's fourth rebuild in about as many months. I've posted on this sad lil tractor before and the results of this latest attempt by the newest rebuilder ended the same as all the rest.
After about 2 minutes of run time with the deck on for only a thin minute the motor started throwing oil out the crankcase breather assembly.
Shut the motor off and went into the shop to call the rebuilder. He now is keen to have me run it on a different muffler. His thinking is that the O.E.M. muffer could be restricting the exhaust enuff to cause enuff back pressure to create blowby and therefore pressurize the crankcase.
I'm working off that theory and will get an aftermarket for it at Tractor supply tomorrow. I'll post back the results in case it is helpfull.
Has anyone experienced this sort of thing with a case muffler? If it turns out to be the culprit all this time is there any way to clean it out?
Any advice, incense burning or consultation with the nut and bolt gods will be greatly appreciated.

I've also posted the motor troubles at the Yahoo kohler forum in case anyone's entertainement starved.

Thanks,
Tim
 

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It's an interesting theory but one that I'm having a difficult time buying into. But in order to humour this guy, pick up one of those cheap pepper pot mufflers and put it on. If the problem goes away, then I'll have to concede. Your next step would be to carefully disect the stock OEM muffler to find out how such a restriction could take place inside. An internal baffle would have to come loose and get jammed over the hole where the exhaust exits.

I would think that you would notice a substantial difference in exhaust tone and in exhaust gas volume if this was to happen.
 

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Discussion Starter #4
It's a stretch but it's the only thing that we're coming up to look at. The engine is exhausting out the muffler and there does,'t seem to be any clues of a mouse nest. We'll see... I'll post on the results of the replacement muffler tomorrow.

Tim
 

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It sounds elementary and I'm sure that this has been confirmed already, but have you checked the oil level? In the past, on small air-cooled engines, I've seen a different dipstick that might fit, but is not accurate as far as how the original one may have displayed the proper oil level, i.e. causing too much oil to be put in, causing the crankcase to become pressurized. It's a long shot, but I've seen and heard of this happening before to people, not just on Kohler engines. Just make sure the oil isn't getting too full, maybe run the motor with a bit less oil for ten to twenty minutes not engaging the mower just more or less standing next to the motor while it's running monitoring everything. A long-shot, but worth entertaining being all you've been through. I certainly think it's worth sticking with it...I can only tell you, if you do and eventually you WILL get it solved, you'll be rewarded by what these machines are known for...reliabile, long-lasting tractors, that someday can be handed down for many generations! ...oh, and they certainly look pretty darn cool too!!!!! -Goodluck!!! -Jon Milwaukee
 

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A friend of mine had this happen with a newly overhauled Kohler in his Case garden tractor, it even blew the dip stick out.. He finally gave up and sold the unit. 20 years later I found out that the crankcase vent valve (reed valve) is frequently assembled wrong when the engine is overhauled and results in pressurizing the crankcase. Drawing air in on the piston up stroke and sealing the vent and pressurizing the crankcase on the down stroke, backwards of what is desired. Have the mechanic reexamine the vent valve assembly (or do it yourself if you can find a diagram).

Don't buy a new muffler to test for muffler pluggage, unhook the muffler and operate it without a muffler.

When the spark arrestor on my chain saw exhaust became plugged with carbon, the engine slowed down, no RPM, no power.
 

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A friend of mine had this happen with a newly overhauled Kohler in his Case garden tractor, it even blew the dip stick out.. He finally gave up and sold the unit. 20 years later I found out that the crankcase vent valve (reed valve) is frequently assembled wrong when the engine is overhauled and results in pressurizing the crankcase. Drawing air in on the piston up stroke and sealing the vent and pressurizing the crankcase on the down stroke, backwards of what is desired. Have the mechanic reexamine the vent valve assembly (or do it yourself if you can find a diagram).

Don't buy a new muffler to test for muffler pluggage, unhook the muffler and operate it without a muffler.

When the spark arrestor on my chain saw exhaust became plugged with carbon, the engine slowed down, no RPM, no power.
Not bad for a first post. :MTF_wel2:
 

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Discussion Starter #11
Thanks all,

I'll give it a hail mary pass and check the assembly. It was suspected by the rebuilder and was replaced on the last rebuild. He might have done it wrong, though why it would be doing the same thing on evry rebuild is a mystery. The guy is walking away from it though....Kinda ****** about that since it was all "we stand behind our work, etc..." on the first rebuild. Maybe it's as simple as an improperly installed reed valve. It was checked for proper assembly on each of the previous rebuilds as a likely culprit. Evrything looked right according to the diagram. I also double checked it with a k-321 sitting in an ariens that I've got lying around. Was the same. I'll still check it though....

The dipstick hasn't been checked to be correct. Would anyone know the proper length of the dipstick in a k-321?
Thanks for the ideas, it's appreciated. I'll report the findings in case it might help someone else down the road.

Tim
 

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Besides being assembled wrong, a "properly assembled" crankcase vent valve can be sticking closed and then ring blow by has no way out but the oil add tube.

Other discussions in Google state that excessively worn exhaust valve guides will overwhelm the EGR valve. Did the rebuilders install new valve guides or oversized valve stem in rebored valve guide? If this was not addressed in any of the rebuilds, it could be the common cause.
 

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Ya, defently check the breather. [think I said that in a thread for a earler rebuild but could be wrong. As for the dipstick. Drain the oil, and put in three pts of new oil. See where it is on the stick. Every K I have takes right around that ammont [and I belive it says it in the manual also] After that, check what the stick shows.
 

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Thanks all,

I'll give it a hail mary pass and check the assembly. It was suspected by the rebuilder and was replaced on the last rebuild. He might have done it wrong, though why it would be doing the same thing on evry rebuild is a mystery. The guy is walking away from it though....Kinda ****** about that since it was all "we stand behind our work, etc..." on the first rebuild. Maybe it's as simple as an improperly installed reed valve. It was checked for proper assembly on each of the previous rebuilds as a likely culprit. Evrything looked right according to the diagram. I also double checked it with a k-321 sitting in an ariens that I've got lying around. Was the same. I'll still check it though....

The dipstick hasn't been checked to be correct. Would anyone know the proper length of the dipstick in a k-321?
Thanks for the ideas, it's appreciated. I'll report the findings in case it might help someone else down the road.

Tim
Whadda ya mean "the guy is walking away from it"? Are you telling me that he isn't going to repair this engine for you so that it works? If so, is he refunding all of your money? I wouldn't be letting that A-hole get away with that. He said he bench tested this engine and it was ok. For how long and at what RPM?

He knew at the time of taking this engine job on that work had been done by someone else just before it was handed to him and that work was found to be unsatisfactory.

At this point, I know what I'd do. I'd contact Brian Miller, tell him what's transpired and then ship the complete engine to him to get to the bottom of this problem. Once I got it back and was satisfied that it was working 100 percent, then I'd be off to the local small claims court and sue that guy for the two-way shipping costs plus whatever Brian charged.

I'd also go after the previous goofball too.

Those guys held themselves out as engine builders, took your hard cash and then walked away. At the very least, you are entitled to a refund of their labour charges. Parts are a different story because you did receive those parts and as long as Brian finds them usable, then they're entitled to keep the money for those parts. Any parts that are wrong or must be replaced due to a workmanship issue, then you're entitled to be re-imbursed for them.

Don't let this guy get away with this. :madpc: :madpc:
 

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Install the breather from the Ariens K-321 and see if it still pressurizes the crankcase. Remember, the oil drain hole goes on the bottom.
 

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A thought I had that ive ran into before on some engines is that most use cast aluminum pistons and once in a while you will find a bad one that has a air pocket in it no bigger than the head of a pin very hard to see especially with carbon build up and they look like a small black spot again no bigger than a pin head . you would be surprised at the amount of blowby this will cause . I generally wire brush the top of the piston and use a flashlight while looking at the other side with a magnifying glass look for even a hint of light while holding the flashlight tight against the other side or just replace the piston if you havent already done so . most places dont if it measures ok and looks ok but alot of them will miss this problem
 

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the k321 on my amf holds exactly 2 quarts of oil if i remember ill measure the dipstick and let you know if needed i can post pics of the dipstick too but i know that kohler had something like 8 different dipsticks that were used on the k series engines
 

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A thought I had that ive ran into before on some engines is that most use cast aluminum pistons and once in a while you will find a bad one that has a air pocket in it no bigger than the head of a pin very hard to see especially with carbon build up and they look like a small black spot again no bigger than a pin head . you would be surprised at the amount of blowby this will cause . I generally wire brush the top of the piston and use a flashlight while looking at the other side with a magnifying glass look for even a hint of light while holding the flashlight tight against the other side or just replace the piston if you havent already done so . most places dont if it measures ok and looks ok but alot of them will miss this problem
I think that these pistons are meant to have that pin hole, design intent.
 

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Ya, I got that mixed up. Some lawnboys have the pin hole as some sort of decompression scheme or something of the sort, not the Kohler...
 
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