Kohler CH740 power issues.

[Scrubcadet10]

Kohler parts are what I would call a reasonable price ( Briggs parts are under priced & Kawakasi parts tend towards over priced ) .
Some will say Kohler parts are expensive so pull the parts out , measure & check everything before you start to order parts.
If you are not feeling confident the post the full list of what you intend to replace.
I am sure there will be enough contradicing opinions to totally confuse you.:laughing:

I have all my opinions ready,
If it ain't WORE don't Replace it.

Let the contradictions begin!.......:licking:

 

[F150Fan80]

Hopefully this picture helps. I just put these on and they have only been used for roughly ten minutes. Basically brand new.

View attachment 46227

Here are some pictures of each piston and the jug they came out of. I haven't tried to put a ring back in each as of yet. I hope to try that later tonight if I don't get really tired first from getting off midnights.
Side one:

View attachment 46220View attachment 46219View attachment 46221View attachment 46222

Side two:

View attachment 46223View attachment 46224View attachment 46225View attachment 46226

ILENGINE, can you tell me which style pistons I have? I think that via the parts diagram I'm looking at now they look like both. Lol

 

[Scrubcadet10]

Looked up images with the part numbers, to me it looks like you have style B, I noticed style A the area around the wrist pin was more rounded, style B
Was square -ish like yours...
:2cents:

But wait and see what others say.

 

[ILENGINE]

The Kohler dealer parts lookup site only shows the Style B rings and pistons. Doesn't appear that Style A was used on your spec number. Something to check is the thickness of the top piston ring. 1.2 mm is the style B and 1.5 mm is the style A,

 

[Scrubcadet10]

https://www.partstree.com/models/ch...p-725cc/crankcase-group-2-24-296-ch18-750-12/

Look at the piston Diagram in the schematic, #32 top left,

 

[F150Fan80]

Top ring is 1.5mm according to my caliper. Looks like I have style A. What was the reasoning for the new style piston? Should I change them out or just re-ring what I have? The pistons look pretty good. They just need a bit of a sprucing up is all.

 

[ILENGINE]

Piston manufacturer may of changed. From what I found the standard size Style A rings are NLA. So may have to convert to style B piston ring assemblies.

 

[F150Fan80]

Piston manufacturer may of changed. From what I found the standard size Style A rings are NLA. So may have to convert to style B piston ring assemblies.

What numbers are you coming up with? So it's looking like I'll need new pistons w/ rings then right? Is the rod the same? I just want to make sure that I can reuse the original rods since there is no need to replace those.

EDIT: Just found these on eBay. https://www.ebay.com/itm/KOH-24-108-14-S-Kohler-Piston-Ring-Set-STD-83mm-25HP-2410814S/173663221847?hash=item286f227857:g:vAoAAOSwcOZb~YzK#shpCntId

 

[Scrubcadet10]

Look at the parts tree link I posted, everything is available and/or got superceded to a new part number

 

[F150Fan80]

Look at the parts tree link I posted, everything is available and/or got superceded to a new part number

I did go to that link. The standard replacement rings for my style piston are no longer available from there either. It wants to supercede to the new style piston and ring assembly. I found someone with NOS OEM standard rings for my pistons on eBay. Those are way cheaper than a new piston and rings. The new pistons use a thinner ring at 1.2 mm instead of what mine uses, a 1.5 mm thick ring.