kohler MAGNUM 18HP connecting rod broke

Hey .I bought a really nice clean engine to repower my mower. it sat until now. Oil must have leaked out over winter . anway connecting rod must be broken because piston not moving. engine still runs really good on one cylinder. what kind of damage am i facing here. I never heard any bang when it broke. engine still runs. is it possible not to have any damge except for connecting rod???

junkman108 said:

Hey .I bought a really nice clean engine to repower my mower. it sat until now. Oil must have leaked out over winter . anway connecting rod must be broken because piston not moving. engine still runs really good on one cylinder. what kind of damage am i facing here. I never heard any bang when it broke. engine still runs. is it possible not to have any damge except for connecting rod???

Click to expand...

Possible yes
Likely no

Do not keep on running the engine as the debris can do a lot of damage to gears cams & pumps.
Pull it apart and have a look.
Once a broken rod exits the crankcase will be toast.
As it still runs, the worst case would be one side is trashed so you remove the pushrods, piston and cut the rod down to make a spacer on the crank & run it as a single

yes i drained oil and no debris in oil i was able to push piston back a bit and cylinder look great with crosshatch. can i split just one half of crankcase to replace the rod?? other side c ompressiom is 135. i cant believe this **** happened after all my hardwork of installing it. oil leaked out through the drain plug . it was 3/8 plug but not 3/8 npt. I always check the damn oil but i was wearing shorts with no pockets and did have any napkins ...

I have no luck with the magnums. original one i lent to someone and they supposedly changed the oil anyway engine grenaded pistons rod crank cam block everyything was in shards and lil pieces.


I bought 2nd engine surplus which i still have . i installed it and engine idle was screaming. tried to adjust governor but to no avail. I tool the hex plug off and the governor wasnt even on shaft. it was just floating around in there. removed engine and took oil pan off to my surprised nothing!!!. the v engines i can get to the crank by removing the oil pan but not on these buggers!!!!


Is it possible to just split one side to gain access??

I forgot to say i took the head off and the head is perfect piston push in about 1/2 inch. what i could see of cylinder wall looked like new with cross hatch.