One of my spark plus is white on my John Deere L120 riding lawn mower?

I assume the mower is a twin cylinder,where one spark plug is operating showing a straw colour electrod and the other electrod is white, which we will call it no. 1
Possible faults.
Inlet manifold gasket loose or needs changing.
Insufficient petrol going to no.1
Compression low on no.1 could be piston ring or valve
Note. you can buy piston ring sealer from a car part shop.
Check spark plug is correct type and gap.
Air pressure test with no.1 on compression stroke ie, both valves closed, a gauge is fitted in plug hole.
Head gasket maybe about to blow around no.1
Always check the simple things first.

Will the off roader
August 2009

are you using the correct mix? Sounds like it is running lean

Tony
August 2009

Check the inlet manifold gaskets for leaks.

John
August 2009