Advice needed for first Kohler engine rebuild

[tntatro 171]

I had a bunch of problems today with the engine. First I think it hasn't been charging the battery. I think the magneto wire wasn't plugged in all the way. I started it and tried different governor spring locations then when I was adjusting the high speed stop the engine died. Then it wouldn't turn over like the battery was dead so I put a different battery in and the starter would turn but not engage the flywheel. I messed with that and got it working and now it won't start. I checked for spark by turning it over with the spark plug touching a cylinder head bolt and I could not see any spark. I checked the points for continuity and it seems fine and the gap seemed to be okay also. I got sick of messing with it for today.

[tntatro 171]

The problem turned out to be the ignition coil. It is new so I'm not sure if there is something going on that caused it to fail. I bought it from isavetractors.com and I think they will replace it. I put the old coil in and it starts right up. I know the connectors from the magneto to the alternator, or whatever that is under the steering wheel, were not pushed all the way in. Also, the small wire connected to the solenoid was only holding on by a few strands. I think I got those things fixed, hopefully I don't keep burning up coils. There is a chance that I got the magneto wires switched because I had to take them out of the plastic piece at some point but I think I put them back right.

 

Yesterday I picked up six more Kohler engines. I got an 8hp, 10hp, and four 12hp for $125. That should keep me busy for a while.

[Shynon 7,459]

1 hour ago, tntatro said:

The problem turned out to be the ignition coil

I have had 2 bad China coils new. I no longer by them. I get them from bat4kids they are not made in china. Have had no issues.

[bc.gold 3,403]

Maybe these Chinese coils require that you install an external ballast to keep them from burning out.

[ebinmaine 67,549]

4 hours ago, tntatro said:

Yesterday I picked up six more Kohler engines. I got an 8hp, 10hp, and four 12hp for $125. That should keep me busy for a while.

AWESOME

[tntatro 171]

I have it adjusted now so the throttle lever at the bottom is about 1,200 rpm and all the way to the top is just under 3,600 rpm and sometimes hits 3,600 and once in a while I see it pop over a little. That seems okay to me. When I mow the rpm goes down to about 3,400, is that normal or should it go back to 3,600? I can tell it's slightly working by the way the engine sounds. I normally wouldn't think anything of it but since I rebuilt it I'm maybe looking too closely. It has a 48" deck so I guess it's going to work a little to turn it.

[tntatro 171]

Here's the piston and bore on the free K181 I got. I had to smash the piston and rod to get it apart. A cylinder head bolt above the exhaust port was stuck and broke off also. If I'm lucky it might clean up well enough to be usable at .030 overbore. It was a standard bore and if it wasn't neglected then it would have been a good one to rebuild. The valves were also stuck.

 

I have two more K181's. One was off my tractor and the other I got with a recent purchase of 6 engines. The one off my tractor is looking pretty good except the piston is damaged and the rod doesn't look so good. The bore is still in spec. The other 181 has a welded block and I don't think it's worth rebuilding. The bearings were sloppy and everything is out of spec. The piston was also cracked. That one must have been worked pretty hard. It does have some good parts though. The note on it from the seller said "smokes, welded block". Apparently it still started.

[tntatro 171]

This looks like the best one out of the six engines I just got. The seller told me that it vibrates. He was told when he got it that it was rebuilt. It probably doesn't smoke because he would have said that. It has a one inch shaft and looks like it has a pull start but there is no rope. Anyone know anything about it? What does it need for the pull start to be complete?

[ebinmaine 67,549]

Looks like it could be a 12 horse that was a S/G motor, not pull start.

Red?? paint under the bracket mount on the dipstick side. Could be orange paint.

Quick Google search shows mid 60s Jacobsen usage.

 

Someone should be able to search that serial number for you.

 

That one is a good score.

 

 

[tntatro 171]

With the pulley looking thing on the flywheel and the starting instructions say to give a firm steady pull, that made me think it was a pull start. 

[ebinmaine 67,549]

1 minute ago, tntatro said:

With the pulley looking thing on the flywheel and the starting instructions say to give a firm steady pull, that made me think it was a pull start. 

I can definitely see where that would lead you to believe that.

 

That thin pulley on the front of the engine looks like the one on the front of my 1267.

 

Pretty comparable engine overall.

I'm no expert by any means but I Wonder if those directions are generic for all Kohler of that series.

Then from there each manufacturer would change whatever they needed to. Possibly that pulley.

[tntatro 171]

I finally got set up to bore some cylinders. The first one I did was the welded k181. I was pretty surprised at how fast and accurate the hone worked. I expected it would take much longer. I brought that one from a way out of spec standard bore to .030 over. According to my cheap micrometer and bore gauge I got it pretty close. That was a practice block that I won't be rebuilding. 

 

The second one I did was the k181 I got for free that was completely locked up. In the pictures you can see that there is still bad pitting. I have it bored about .004 away from .030 over. I'm going to take it to .0025 under and see how it looks and judge from there whether to rebuild it. The piston was near the bottom of the stroke so I don't think the pitting would affect the compression but I would like to see a bit less pitting to rebuild it. I may just throw as little money as possible to get it running decent and beat on it.

 

The next one will be the k181 that was on my Wheel horse. It is a standard bore and has reached the maximum wear limit and also the maximum out of round limit. It needs a new piston and rod anyway so I'll try to take it to .010 over. The crankshaft reached its maximum out of round but the crank off the locked up engine is a little worn but hasn't reached the maximum wear limits.

[DerekN 5]

Are you using a cylinder hone to bore the cylinder?

[tntatro 171]

2 minutes ago, DerekN said:

Are you using a cylinder hone to bore the cylinder?

Yes, I have a used Sunnen AN that I tried for the first time.

[tntatro 171]

It didn't clean up very good. I think I'll put this one away until I'm done with the others. I didn't get as accurate on this one. The top of the bore is still .001 away from spec while the bottom is pretty close to spec. I think it would work better if I could flip the block and hone from the bottom also. I may build a frame to mount the blocks to so I can try it that way. The next one will be the k181 that I plan to use. I think I can get it good enough. I'll wait until I have the piston to bore it.

[tntatro 171]

Just giving an update on my first rebuild. I bought a rusty old B-80 for $100 that had been run with no oil and the rod broke. I put the K241 on it and it seems to run pretty good. No smoking or knocking and starts easily, idles nicely and everything. The only thing about it is that it has (I think) overheated two more times, not when I was using it. After the first time I rebuilt the carburetor and put a bronze bushing on the throttle shaft thinking that excess play was causing it to run lean. The second time was recently. I don't know what happened, I was just told it was sputtering and then stalled, then started later and parked it. It starts right up and runs fine for me but I don't use it a lot. He also caught the deck height lever on something and bent it out of place, maybe the belt had more tension and worked the motor too hard. It has about 32 hours on the meter now. Maybe I'll adjust the carb settings a little and re-check the points. I'm wondering if I should pull the head and check it out.

 

I've rebuilt two k181's. One was the rusty pitted bore. That was not a good idea. It smokes worse than my engines that need rebuilt. It has less than an hour on it but I'm going to have to get a .020 block and bore it to .030 and swap the parts. The other runs good but lets out a puff or two of smoke when cold. I left it standard bore and put in a used piston and rod. 

 

Next I have another k181 and have all the parts already, just have to bore it and do the valves. I just ordered parts for a k301. It's getting a nice rebuild also, at least I hope it turns out nice. Then I'll do one more k301 and maybe take a break from the Kohlers and do a 17hp Briggs on my L100 John Deere.

[tntatro 171]

Just updating the K241. It is still on the B80 and has almost 70 hours. The stalling problem turned out to be cobwebs in the gas tank that plugged up the hole. So far it runs great. I did have an issue with a small amount of oil seeping out the cylinder head. I could see a dark spot on the top fin. When I first rebuilt the engine I forgot to re torque the head bolts and it was leaking then. I just re torqued them and thought it was fixed. I'm not sure if it was leaking because of that but I put on a new gasket, ran it for 20-30 minutes and then re torqued them when cold. That was at about 65 hours. Hopefully that fixed it.

 

I've since rebuilt three K181's and two K301's. One K181 was a waste of time and money because it had a rusted bore, another I decided to rebuild cheaply and it came out okay but wasn't worth it to be cheap about it since doing it right would likely make it last a very long time. I might have saved around $100. The third K181 I rebuilt with all new old stock Kohler parts and it is on a tractor now with around ten hours on it. I just ordered another K181 block to redo the first one.

 

The K301's came out pretty good but had some problems at first. The first one vibrated badly. It rattled the hood and I could feel it in the steering wheel. The previous owner removed the balance gears. I bought a counterweight for the crankshaft and had the machine shop install it. Now it's fine. The second one had a deep rubbing sound when I first started it. I pulled the flywheel and it was rubbing on the stator. I then noticed that there seemed to be play in the crankshaft so I had to take it apart. It turned out that the aftermarket rod that I bought was standard instead of .020" under. I rechecked the order and I did order the right one, I didn't measure it before installing. I got lucky that the flywheel was rubbing on the stator, otherwise I would not have caught the error. The second one has the balance gears and as far as vibration it is very similar to the one with the counterweight. So far I'm pretty happy with the K301's and one of the K181's. 

[ebinmaine 67,549]

Your tenacity is admirable. Keep up the good work. Thank you for the update.