Everything should be available for rebuild. I would definately go this way for multiple reasons
1 It is my belief that no motor will beat a k series in reliability and durability.
2 The modern engines are designed larger for the same hp.
3 Things were manufactured to last with the older engines. Modern engines are manufactured with less quality so that the manufacturers can make more money selling parts.
If you decide to replace the engine, I would find a donor machine with a good engine that is a k321. There are alot of macines and k series engines out there.the k321 was used in alot of machines but the diference in the engines is the component.
As far as where to look online for parts or engines, stay away from ebay and amazon. They advertize oe parts but they are usually chinese. If thes parts work, its only temporary. I deal with isavetractors.com, repairclinic.com. ,and stens for new parts. I usually try to locate used parts to keep my machines as original as possible.
The oil burning issue is likely a worn head gasket or piston rings. Both will make the engine act tired. Both can result in lose of power. Both can result in hard starting. Both can cause an engine to burn oil. You can easily check your compression to verify if it is one of these two. If you remove the head and discover a gasket issue, this is a cheap and easy fix.

 

I personally would always go the route of rebuilding the original engines/motors in my l&g tractors over replacement/repowering a tractor. Replacement/repowering a tractor that had a k series engine originally means more fabrication and cutting up tractor frame to allow room for the crankshaft pulleys to operate/function properly. In my case, more headaches than getting a job completed efficiently and if I choose to sell tractor or 2 I know that the engine will last the next owner of tractor their lifetime and beyond.

 

REBUILD! Buy a hone and get a rebuild kit. Done deal and it will outlast you.

Kohler K321 engine a 14hp rebuild kit complete | eBay

 

I prefer going threw ISAVETRACTORS.COM or Hapcoparts.com for my John deere L & G Tractor parts; unless I have to go directly to a local JD dealership for certain parts.

 

I just used that link for a reference.

 

Thanks to all for feedback. Sounds like rebuilding is the way to go. Thought I would ask the "replacement" question just in case there was an easy and quality upgrade that would make sense without lots of modifications.

Certainly appreciate the suggestions for vendors to get some quality parts.

I think a minimum repair will be new rings as it has serious blow by and uses quite a bit of oil but I suspect I will have it bored out for an oversize piston. Also think I have some issues with the ACT (automatic compression release). Occasionally it will back fire and quit running, when attempting to restart it would appear to have absolutely no compression. After cranking a while the compression seems to come back and away it goes, been doing this little trick for years. LOL

 

Personally the K engines are tougher than nails. When they start smoking it is stuck or worn rings. I would measure the bore for size and out of roundness. In every case of a rebuild I have done it was nothing more than rings and a hone.
Check it before you do a bore and oversize piston.
Just my .02$ But I'm cheap.

 

I am not cheap but agree completely with @mopar65pa . I used to rebuild them myself but have to many other projects and hire it done. Engine can be overhauled for $900-$1000. Last one I had overhauled had a broken rod but did not poke a hole in the block. I had recently bought the tractor and it was not the original engine in the tractor. Balance gears were missing in the engine. I had it rebuilt for just over $1000 (parts and labor). My 2 cents ... rebuild it if it is rebuildable.

 

I took a look at the ISAVETRACTORS.COM site and found a complete rebuild kit including the carburetor for $249 which seems more than reasonable. Based off feedback it would appear that people responding to my questions have used these parts and seem to be happy with the performance of these parts. Is that a fair assessment? I would suspect these parts at that price level must be "off shore" parts rather than original parts manufactured by Kohler. I think I did find one site that I thought had the original Kohler parts and just the piston alone was $149, they didn't have a "complete rebuild kit" as such to compare to. That price level could quickly escalate to the point where it would be cost prohibitive to do a complete rebuild. So just maybe looking for some reassurance that ISAVETRACTORS.COM or similar vendor parts are of acceptable quality and do work well.

 

The parts from ISaveTractors , I think are considered to be the best you can get...and you can call and ask for help

 

I have bought from them many times.

 

Just a quick update......, pulled the engine and tore it down this past week. Had quite the surprise when I pulled the head off it, the cylinder was badly scored on both sides of the bore. Upon removing the piston, I found that both the piston pin snap ring retainers were missing so the piston pin was floating back and forth causing the scores, one side is way worse than the other. I'm thinking it is so bad that it is more than boring will clean up, I think they only go .030 over. This certainly explained the severe blow by that it had, amazingly the rings were not broken. I did not find any pieces or complete snap ring retainers in the oil pan and there does not appear to be damage from the retainers between the piston and the cylinder wall so I'm not sure if they were left out when the engine was assembled or what happened. A good friend of mine bought the machine new and I'm 99.9% sure the engine has never been apart before so it's a bit of a mystery. I'm actually surprised the thing run as good as it did, considering how badly the cylinder is scored.

Anybody had any luck in putting a sleeve in these engines? It is a kohler K321 14 horse.

 

Bore it to a 16HP. Or just find a K341 as we have said.

Sorry for you luck.

 

I dont know for a fact, but I thought there was a lot of bore room on those for oversize. Maybe im thinking of the 12hp blocks...

 

Ingersoll444, I think you're right that there is plenty of block for over bore but my quick review is they only go .030 over on replacement pistons. I'm pretty sure that one of the scores is way more than .015 so I would guess that could be a problem.

mopar65pa, never thought of boring it out to a 341 16 horsepower but that seems like a great solution. I do have a Kohler manual covering all the K series engines and noticed the head for the 321 has 9 bolts and the 341 has 10 bolts so it would seem to dictate that I would have to retain the 321 head gasket. Wonder if the larger bore would be a problem with the K321 head gasket? The bore would go from 3.5 to 3.75. I don't have the engine available to look at right now so can't really make any inspection on how well it would or would not accept this larger bore. Will be back to where I have the engine later this week so will look at that when I am there.

Thanks much for the responses and a Merry Christmas to all.