Kohler K241 - Damage and Rebuild opinions wanted

[oldredrider 2,548]

15 hours ago, squonk said:

Crank can possibly be ground to .020" under and use a .020" undersize rod. Cylinder can be sleeved. @oldredrider

The last Kohler I had sleeved was a K341. Already bored .030 and had deep gouges. My machinist sleeved, bored to standard size and recut valve seats. Charged me $80. This was before we became good friends and now share a common interest: Wheel Horses. He now has more of them than I do. 

The hardest part nowadays is finding a machine shop to work on small engines.

Fortunately,  my machinist has a boring machine he leaves set up for my work.

Edited August 17, 2021 by oldredrider

[OutdoorEnvy 1,522]

13 minutes ago, 953 nut said:

How much oil was in the engine? How many hours was the engine run following the rebuild? With everything else being well oiled and that much aluminum build-up on the crank it looks like it wasn't getting enough oil to the crank.                  Wonder if the oil hole on the crank was placed away from  the cam?

           With the block already being +20 needing to be sleeved and the crank being questionable I would start looking for a replacement engine, You will end up being north of $ 450 to fix this one. 

 

Not sure on the exact oil amount.  What I drained out was very thin.  I just picked this up recently.  It hasn't run in decades...No idea on hours...Head when pulled did not have excessive carbon build up at all.  Yeah if I can't figure out a cost effective way to get it running I will look for a parts tractor with a better kohler candidate.  They pop around here somewhat regularly for reasonable pricing.  Especially John Deere's.  Any 10-16hp single cylinder kohler would work for me. 

 

9 minutes ago, squonk said:

Even IF you could run it with that gouge, you still need to check that cylinder for out of round and taper. Who knows how many hours are on it since it was rebuilt once

If I get a bore gauge would I have to measure with a micrometer or would a digital caliper that goes to thousandths be acceptable accuracy?  Also was thinking the caliper could measure the crankshaft journal?

 

thanks again all the help and suggestions...it's fun learning this stuff

[953 nut 55,056]

2 minutes ago, OutdoorEnvy said:

oil amount.  What I drained out was very thin. 

Could be the fuel pump diaphragm was leaking gas into the oil and that reduced it's lubricating ability.

5 minutes ago, oldredrider said:

My machinist sleeved, bored to standard size and recut valve seats. Charged me $80.

You are a lucky man, need to be good to him. I had to pay more than that for a + .030 bore job alone.

[WHX?? 48,761]

I use these guy with a cheap digital calipers. Same caliper to measure cranks. I'm not proficient enough for precision work but gets me in the ball park. If in doubt let the machine shop measure. 

Telescoping Gauge Gage Set Tools 6 Pcs 5/16'' - 6'' Range Micrometer Precision T-Bore Hole Gauge: Amazon.com: Industrial & Scientific

 

Regular bore gauges are best but a good one is $$ and out of reach for the novice hobbyist. Lots of you tubes on how to use one one if interested further. 

 

15 minutes ago, oldredrider said:

my machinist has a boring machine he leaves set up for my work.

Buy that man a case of beer! 

 

15 minutes ago, OutdoorEnvy said:

thanks again all the help and suggestions...

Your 

 

15 minutes ago, OutdoorEnvy said:

it's fun learning this stuff

Us too! 

[oldredrider 2,548]

1 minute ago, WHX?? said:

Buy that man a case of beer! 

 

I would but he doesn't drink! He does however, have a supplier of that tasty peach stuff and always calls me before he places an order!

[richmondred01 2,237]

I’ve been rebuilding these old Kohlers for 40 plus years. I still do 4-5 a month in retirement. I don’t believe in wasting my money or other peoples’ money (that includes not overlooking issues in an effort to save a few bucks.) Pay me now or pay me more later. With that in mind, after looking at the thread if you came to me with this engine I would say if you wanted it done right it would need to be sleeved and the crank ground. (You are already over .020 and that chip looks like .030 won’t take it out.) While in you have the engine torn down you might as well grind the valve seats and check the guides. If they are out of spec replace and ream new ones. The rebuild will be costly. If it was a k341 I would say it’s worth it but not a k241 wheel horse spec. (However, not all Kohler blocks are the same. The pto sides on some are machined and bolt patterns are different. Even something at simple as the placement of the oil dipstick will make a difference as to if it will fit into the specific application)  Therefore, for some people finding the correct block is near impossible so the old block must be used and the additional machine work is required. 
Unless you have an emotional attachment to that engine, I would find a good running k301 or k321 and drop it in. That will give you an addition 2-4 hp as a bonus.
That’s just my opinion I’m sure there’s a lot more opinions out there and I certainly hope that helps and I won’t be canceled by the recent wave of “wokeness”.

All the best. 

Edited August 17, 2021 by richmondred01

[OutdoorEnvy 1,522]

11 hours ago, kpinnc said:

Does you block have K241 or K301 on the PTO side? Many 10hp engines used castings for 12hp.

 

I checked and it isn't marked either way. 

[OutdoorEnvy 1,522]

19 minutes ago, richmondred01 said:

Unless you have an emotional attachment to that engine, I would find a good running k301 or k321 and drop it in. That will give you an addition 2-4 hp as a bonus.

 

Thanks @richmondred01 I was hoping you would chime in with your opinion on it.  That's kind of what I was thinking.  This isn't my main user so I can afford to be patient for a good used engine to come up.  I see deals pop up in the $100-200 range around here for non running garden tractors that should yield a kohler with good compression at some point.  I may just wait out the right deal... thanks again.  I appreciate your input sir! 

[tunahead72 2,403]

Great thread, guys! 

 

[Snoopy11 5,714]

22 hours ago, OutdoorEnvy said:

Alright more pics...it ain't good either.  So it's had a rebuild already.  which confirms why there was little carbon buildup on the head.  Piston is .020 over already.  It also has a small chip in the wall you can see on the last pic pretty well.  So is it safe to say this block is done?

 

 

 

 

 

 

 

 

 

 

Looks like some common aluminum to me...

 

Soak that little A-hole (i.e. crankshaft --particularly the journal) in some muriatic acid (you can get this at any hardware store, including lowes in the paint section), wait until all the aluminum has come off (you will visibly see the aluminum bubbling off... but might take a while). Use fingernail file to go over the crankshaft journal all the way around. 

 

Here is the deal. When dealing with crankshafts, you never want your fingernail to hit any material. If your fingernail goes into a scratch... not so bad... this can actually give extra oil clearance, which can be a good thing. Once you go over the journal with a fingernail file, it should be smooth, possibly with some light scratching. This is fine. 

 

ANY time you clean with muriatic acid, you also want to soak it in a baking soda water mixture, very heavy on the baking soda... and then dry it, and use motor oil to rub on it or assembly lube. 

 

You never want to rebuild an engine if it has aluminum on the crankshaft... oil clearances will not be right.

 

I would end up rebuilding and saving this engine... in spite of people saying how much work it would take... but that's just me...

 

One of my Tillotson engines was 10 times worse than yours overall. Now screams 8-9 thousand rpms. 

 

Don

Edited August 17, 2021 by Snoopy11

[WHX?? 48,761]

3 hours ago, Snoopy11 said:

rebuilding and saving this engine...

I would too just for the challenge and a shelf spare when @pullstart blows one up at plow day.  The 241 is just one of my favorite engines. I have no idea why. 

 

Sorry Snoopy that crank gets ground or a donor no doubt. I would want to start with a perfect crank.  Sides SWMBO gets quite miffed when she finds her nail files in the shop. I got the frying pan once just 'cause my ignition file looked like one! 

 

For a 25 clam workin tractor tho Outdoor I think yours &  Richmond's idea is best. 

[Snoopy11 5,714]

19 hours ago, WHX?? said:

 I would want to start with a perfect crank.  

You might... and so would I... but I have done this on various engines, with very good engine performance over the long run. Never had a further issue after cleaning the crankshafts...

 

You have to consider, race guys break rods all the time... but they don't replace crankshafts all the time. There is a method to their madness... 

 

Don

Edited August 18, 2021 by Snoopy11

[squonk 41,018]

Cleaning the crank is fine. But you better check or get it checked with a micrometer for out of round or you just going to blow it up again.

[Snoopy11 5,714]

On 8/18/2021 at 3:39 PM, squonk said:

Cleaning the crank is fine. But you better check or get it checked with a micrometer for out of round or you just going to blow it up again.

Fergot to say that...

 

Thanks Squonk 

 

Don

[OutdoorEnvy 1,522]

Well just an update but I have had no luck so far finding a good used Kohler engine.  It really sucks that John Deere's use that narrower oil pan for their Kohlers.  I am feeling impatient though and a 212 Predator engine to get her driving is looking more tempting by the day...trying to stay the course though...time well tell which wins out...

[953 nut 55,056]

11 hours ago, OutdoorEnvy said:

It really sucks that John Deere's use that narrower oil pan for their Kohlers. 

Jay @JPWH overcame that problem in one of his posts. See page 4 of the post below.

 

[oliver2-44 9,678]

@OutdoorEnvy If you can get a good small base engine for a good price I wouldn’t pass it up. You can easily make an engine Mount across the existing frame. Believe it or not I have a poore onl blue 953 parts machine that some PO used 2 Oak 3/4” x 2” stringers to set an engine on. 

[OutdoorEnvy 1,522]

8 hours ago, 953 nut said:

Jay @JPWH overcame that problem in one of his posts. See page 4 of the post below.

 

 

That was an interesting thread.  Thanks for sharing.  JD's in my parts pop up pretty frequently.  I passed on checking out a 212 and 214 that I now may lose sleep over...I'll put them back on the list for options.  Rigging up a motor mount seems more feasible than waiting out the perfect replacement at this point.  

[953 nut 55,056]

4 hours ago, oliver2-44 said:

Believe it or not I have a poore onl blue 953 parts machine that some PO used 2 Oak 3/4” x 2” stringers to set an engine on.

[OutdoorEnvy 1,522]

Well a decision has been made to rebuild the K241!  I've lost hope on a better replacement showing up.  I want to retain the 10hp to be a backup mower to my 312 so decided against the smaller predator swap.  This will be a little roll of dice as I am not taking to machine shop for exact measurements.  The block, cam, crank, etc. all seem to be fine with no damage I can tell, other than the cylinder wall chip below the ring travel line previously in thread.  This was previously rebuilt with a .020 over piston and a .010 under connecting rod, will replace with same.  The hours I believe was low as the carbon build up on the head was not a lot.  The oil reservoir was low on oil a lot, but not drained.  So I think this was ran low on oil and the connecting rod couldn't take the heat and she gave.  The crank journal cleaned up well with muriatic acid and has no damage or scratches.  I will be doing a valve job as well with original valves as they cleaned up well.  Also will hone the cylinder wall as well.  So this will be a budget build gamble but I just kind of want to see if it'll work.  And if I waste a $100 on the kit then that's alright.  It gives the boy and I something to do anyways   

 

 

[WHX?? 48,761]

Not to be Debby Downer here Outdoor but @Achto is doing a 181 and having a hard time finding a 20 over piston. Don't know if they are hen's teeth for 241 or not. Squonky says parts are getting scarce for the small blocks not sure about the big blocks. 

I admire your give it the old college try tho. You get a new standard rod I would plastigage it just for drill. Just for inspiration I threw a rod in a 241 once and did exactly what you are doing and to this day it runs well. Everybody here told me I was nuts for using this block but no guts no glory and I ain't flying this tractor at 33,000.

Good luck and keep us posted please. 

Edited March 3, 2022 by WHX??

[squonk 41,018]

+.020 & .030 pistons still available for K241 in aftermarket. All sizes avail in gen. Kohler but $$$$$. Big block parts still available.

 

[OutdoorEnvy 1,522]

@WHX?? Thanks!  .020 over piston and .010 under connecting rod are already ordered and on the way!  So getting the right sizes doesn't seem an issue right now, assuming the right ones show up of course.  I'll post updates. 

 

For budget purposes here's where the project is at:

 

Tractor C-100 = $25

Engine rebuild kit = $100

Carb Rebuild kit = $10

So $135 if we get a running C-100 won't be too shabby...

[Achto 27,502]

Hopefully the rod blew because it was low on oil.  I would want to check the crank pin to see if it is out of round before I assembled it. An out of round pin will also cause an early failure of a rod.  I usually measure the crank pin in at least 10 different spots with a micrometer to check to see if it is true. Specs say .0005" tolerance on out of round. You could use a caliper for this as well but it won't be quite as accurate.

Edited March 3, 2022 by Achto

[953 nut 55,056]

9 hours ago, WHX?? said:

You get a new  rod I would plastigage it just for drill.

         One person's 0.010 under may not be the same as the previous builder's 0.010 under. There can be some variation in aftermarket parts. Pick up some green Plastigage ( 0.001 - 0.003) and check your clearance to be sure.