[4]

Kohler 25 hp issues

[3]
[10] Like what you see?
Click here to donate to this forum and upgrade your account!

Blackhawk

Active User
Registered
Joined
Oct 20, 2012
Messages
254
[video=youtube_share;JY1XTQCawBo]http://youtu.be/JY1XTQCawBo[/video]

Think I got a big problem here, what do you think
 
D

Deleted member 20190

Guest - Please Register!
Guest - Please Register!
The end play in the crankshaft may not be a problem. Is it possible that the end play is controlled by a shim or thrust bearing that is now gone from the oil pan where it has been chewed away??
 

ultrapan

Active Member
Registered
Joined
Nov 24, 2012
Messages
22
What you call the oil pan is the crankcase cover . without the cover on there will be excessive play as illustrated.Install a new cover and check end play.It will most likely be normal
 

JimDawson

Global Moderator
Staff member
H-M Platinum Supporter ($50)
Joined
Feb 8, 2014
Messages
7,893
+1 what Terry said. The end play is set by the distance between the main bearing thrust surfaces, at least one of which is known to be worn. The flywheel side main bearing is probably just a needle bearing or maybe even a bushing, with the case acting as the thrust bearing. I would machine the case, and put in a home made thrust bearing. Bronze or steel would work, maybe backed up with hard steel shims. Or you could buy an actual thrust bearing and machine the case to fit. Something like this: http://www.vxb.com/page/bearings/PROD/Kit8676 I'm guessing somewhere between 5 and 10 thousandths would be about right for the end play when everything is bolted up.

I would finish the teardown, and see what it looks like on the other end. To get the flywheel off, take the nut off, and then pop it with a hammer in about 3 places on the top, not on the side, careful not to break the fins. Don't beat on the threaded end, it will mushroom. Normally they pop right off.
 

chuckorlando

Bronze
Registered
Joined
Nov 24, 2013
Messages
1,631
Chances are theres no "bearings" in it at all. Just a thin bronze, brass type deal that the crank rides on. I have a 24hp kawi tore down here now off one of my mowers. Same idea. Thats a 2-4000hr motor in tough comercial conditions so I dont think it had 250hrs on it. It should most likely have a low oil cut off on it to prevent it from running dry on a hill. I dont think you got the whole story, or something did not work right on it. At any rate well worth the repair. Get the case and throw it together. Once the cover is on the crank play will be all but gone.
 

joconnor

Active User
Registered
Joined
Dec 13, 2012
Messages
75
Hi Jim
Check the oil pump. I have one of those that lost oil pressure. The gear inside the pump spun on the shaft. This one has on oil pressure shut down switch so there was no engine damage. If there is no such switch on yours that may be the problem.
 

ultrapan

Active Member
Registered
Joined
Nov 24, 2012
Messages
22
I would not machine the case cover as JimDawson recommends I would replace it. It is the main bearing and you have already demonstrated there was metal transfer,a new cover will provide a new thrust face and a new bearing surface.
 

rgray

Active User
H-M Supporter - Gold Member ($25)
Joined
Nov 26, 2012
Messages
1,197
I did a kawasaki 620 engine that did about the same thing as your kohler. It was built just like that the parts even look very much the same.
It had a sleeve bearing on the flywheel side and the pto side had the crank just running in the aluminum. It seized the crank to the case from low oil use. I polished the crank up on the lathe with 600 & 800 sand paper. I bought two of the bearings for the flywheel side...installed one in each side. Machining the pto cover out to accept the sleeve type bearing.
Replacing just the cover was not an option on the kawasaki as the block assembly was sold as matched set. Not sure but the kohler is likely the same way.
 

Chiptosser

Active User
Registered
Joined
Dec 12, 2014
Messages
57
I am going to assume that this is a vertical shaft engine. If it is, then the side loading from a belt can wear the bearing surface out of round.
If you have a end play problem, then you have a lubrication problem. Most likely, oil not being changed when needed.
Check the side cover for excessive wear. There is going to be some wear from general use.
There are clearance grooves, around the crank bearing area, to allow lubrication to the the bearing surfaces. With the side cover tight on the block, measure the end play.
These engines will tolerate quite a bit of end play.
If the thrust area is excessively wore, then this area can be welded and filed, milled to take up excessive play.
If the upper or lower bearing bore is wore excessively, they can be bored and a teflon coated sleeve bearing can be installed.
This is how I repair engines for the lawn mower racers and tractor pullers.

Dale Kohler
 

Chiptosser

Active User
Registered
Joined
Dec 12, 2014
Messages
57
I should have look at the vid, your engine is a horizontal shaft and was ran low on oil.
Check the oiling circut for aluminum fineings.
The side cover is repairable as mentioned.

You can use muriatic acid to clean the aluminum from the crank. Warning! do this outside, have plenty of water to rinse with and you may want to use rubber gloves.
Don't do this on your concrete it will eat it, get the idea?

I would change the rings, with the hours on the engine. Check the outside of the cylinders for grass and oil accumulation. A common problem with mower engines.
 

Blackhawk

Active User
Registered
Joined
Oct 20, 2012
Messages
254
Thanks for all the replys, you guys got me really thinking on how to proceed with this build. Here is what I'm dealing with
1. Got engine for free
2. Broke for the next few months
3. Got a mill and lathe (I'm a beginner)
4. I have nothing to put the motor in yet.
5. Have plenty of time, I'm retired.
6. i got a powder coating gun and access to an oven the size of a former east block Russian car ( I got to visit east Germany before the wall came down)
7. I was able to download a repair manual from kohler( thanks to whoever suggested that.(john deere makes you buy them)
8. I got anwirefeed welder that I've never used.
I can just inspect and replace what's needed to get it running or I could do a complete tear down or do something wild and do like someone suggested and refurb the parts I got. That would give me experience using mill and lathe.

just some random thoughts

lanham
 

Blackhawk

Active User
Registered
Joined
Oct 20, 2012
Messages
254
One more thing, the drank was not working out so well so I filled a bucket with coals and will home brew some lye to get the rest of the aluminum didsolved

lanham
 
D

Deleted member 20190

Guest - Please Register!
Guest - Please Register!
One other point to consider before deciding to refurbish the existing end cover is that you don't know the dimension for the internals of that cover. In other words, if you had a plan in place to repair that cover, to what dimensions would you make the thrust bearing portion of the cover? That information will not be readily available anywhere, yet those dimensions will be critical. I hate to say it, but your best bet might be to get the used cover off of eBay if you can afford to go that route and if that cover is in decent shape.
 

chuckorlando

Bronze
Registered
Joined
Nov 24, 2013
Messages
1,631
IMO it almost aint worth the money to do a full re build. Do you own a Mic for the cylinders? You only have a few thou in spec o they need to read correct and not just close.

If I was you, I would order the used case cover and check it asap so it can be returned if no good.

Unless your bored and just want something to work on, it's gonna run about a grand to rebuild that whole engine and you can buy a short block for it for 700 or so. It's 1500 dollar motor new

Price really is determined by what you mean by full rebuild.
 

Rbeckett

Silver
Rest In Peace
Joined
Sep 24, 2010
Messages
2,605
One point to consider if you do decide to make a thrust washer to take up the excess end play created by the impromptu "Machining" of the inner case. Mill it off even and square and slip it back into position and measure the total amount of distance the shaft will move and make a sintered bronze or oilite bushing that will fill that gap less about .008 to .012 and call it good. Welding that will never work because you will never ever get the metal to give up all the oil that has soaked into it over time resulting in a poor quality weld with an overheated casting. We used to repair them like that all the time on Scag Commercial mowers down here in the south and the repair usually lasts longer than the rest of the engine. We tried baking the casting, soaking, pressure washing and any other of a myriad of ways to clean that surface and we could never get a good clean surface to weld on to create a build up. The bushing is very similar to the thrust bushings that they install at the factory only considerably thicker to make up for the lost material from the" machining" and subsequent milling to square off the damage.

Bob
 
[5] [7]
Top