520H

[whdave 1]

Well I pulled the plugs and no compression in the rear cylinder. Tore motor down and found rear rod blown to pieces, this tractor ran on one cylinder since I bought it a few months ago. Now I am looking for a rod and piston for the motor, 20 horse onan. I would like to change both rods and pistons and just throw a light hone on the cylinder walls. There is no ridge at all, cylinders are glazed but great. Any one know where to find 2 rods 2 pistons and a pan gasket. Thanks for the help. Dave P.S. Why would only one go and not both???

[rickv1957 75]

Most small engine shops should be able to get you the parts,Rick

[Kelly 1,033]

Dig deep into your wallet, I just picked up a pan gasket, intake, exh., and a carb base gasket today all Onan stuff and it was $73 A complete gasket set was near $200 and a rebuild kit was $950

[sorekiwi 761]

I had one that did the same thing. Drove fine on one cylinder, no nasty noises. I fully expected the motor to have the common valve seat problem, but it turned out to be a broken rod.

Watch Joes outdoor power on ebay. He often has Onan parts for sale, a pair of pistons and rods usually sell for between $40 and $60. There are several different rods used in the Onans, so it would be prudent to replace them with a matched pair to keep it balanced.

I bought another motor that had a bad valve seat, and used the rods and pistons out of that.

My engine had very little wear in the bore as well. The Onans are a very good motor, and seem to be relatively trouble free in other applications. The general consensus seems to be that in the Wheel Horse installation, the rear cylinder doesnt get enough cooling and so gives problems.

Onanparts.com should have everything you need. You can buy the gaskets individually, the gasket set is ridiculously expensive. Rings will cost you about $30 per piston. Actually he sometimes has used parts as well, and may be able to sell you some rods.