Bent push rods

[Freddie21]

Hi All, What would cause a Kohler 25hp engine to bend two push rods? I am considering buying a used mower with this issue. Don't know if in one cylinder or both.

 

[Rivets]

The two most common causes of bent push rods are, adjuster nuts coming loose and valve guides migrating upward caused by head overheating due clogged cooling fins.

 

[Freddie21]

Thanks, how would I repair the guides? Matter of just pushing them back in?

 

[Rivets]

If both guides have migrated, I would replace the head, as there has been some severe overheating. I have press guides back into place and then peened around them to hold them in place as a temporary repair, but only do this if the customer understands that this is not a permanent fix and problem can happen again, NO WARRANTY.

 

[Freddie21]

Can they go in without a press? I have seen how to peen them. Thanks again for your help

 

[Rivets]

Depending on how mechanically inclined you are and tools you have. I’ve seen them done with a large vice and some DIY guys pounding them back down with a hammer. Technicians and DIY guys do things differently, because we warranty our work. Remember there are other things you should do to do it right. Clean the heads, especially the cooling fins, recut the valves and valve seats, lap the valves, new rods and gaskets, set clearance. Most of these need to be done, whether you fix or replace the head.

 

[Freddie21]

I have done all but recutting the valves. I have good heads for the single Kohlers, but not a twin. May pass on this.