Kawasaki motor issue/ rebuild

I've got a John Deere z810A with a Kawasaki FH661V-BS06-R motor with less than 600 hours. Mower is in very good shape.

It started running rough and took it to a local shop. Was initially told it was an electrical issue, now they are saying that the motor is shot. Said the compression test and leakdown test showed one cylinder was bad.

Finding information (crank shaft length and diameter) is dang near impossible.

Wondering if just having this motor rebuilt will be the most economical approach.

Any advice or info or anything?

Thanks

Maybe a second opinion? That motor should be in its prime. Maybe a loose valve, bent pushrod? Head gasket?

Yes, definitely get a 2nd opinion. Just because 1 cylinder doesn't have good compression, doesn't mean the motor is trash.
Just like Tom said, could be a valve issue, head gasket issue.

X 3

Should be 1.125" diameter on a mower that big.
The JD specifications will tell you more than the Kawasaki one will.