Wheel Horse motor oil

[Jeepster_nut]

I got a 1989 310-8 Wheel horse riding mower with bagger for free. Its in good shape and runs well, only the Kohler 10HP Magnum motor smokes after I let it idle then go to full throttle.
I assume it's the valve guide seals. What oil is best for a tired motor such as this? It calls for 30 weight. Can I use 20w50? It runs great after it goes to full throttle- it stops smoking for the most part.

 

[saberz]

I've heard MMO added to mowers seems to make the smoke stop amongst other things(better lubrication as well, cleans up any gunk in the engine).


I'll let others chime in, if you make it to thick of an oil a mower motor will struggle.

 

[Jeepster_nut]

Sorry, but what is MMO? Oh Marvel Mystery Oil? How much should I add? It is a 2.5 quart sump

 

[JTK]

I'd run 15w40 in it, but 20w50 would probably do fine should you not have to start it in extreme cold. Kohler tended to stick with SAE30 for the K and Magnum series, but some OEMs such as my Case garden tractor spec'd 20w40 as being fine for the Kohler K-series. The Magnums replaced the K's around 1988.

Joel

 

[Jeepster_nut]

So 15w40 is HDEO used for diesels, correct? Diesel oil just cleans better than conventional oil right? I will change it out with some Rotella and a little MMO too.