Did you replace the plugs in both, or just the X320? How'd they look?
The Kubota had the stock Champion RN14YC plugs that were totally black from being started with the choke several times and moved around the dealership yard for three years. Never warmed up properly or worked.
I warmed up the engine, drained the oil and put the BPR5EiX-11 plugs in that had been in the X320 for 10 hours.
The -11 is a designation for .043” gap and is for electronic ignition only. Metric mm to inches; 1.1/25.4= .043
I couldn’t find another set of the same plugs or the same without the -11, but got BKR5EiX which are shorter with a 5/8 hex instead of 13/16 and .032” gap. Those fit in the X320, but if they were any shorter it would be a no go.
IMO the engines start quicker and run smoother with iridium plugs.
Yesterday I took off the little 16-6.0-8 front tires and put on 18-9.50-8. I tend to bro-truck everything and now the Kubota looks mean.
The tires are a big for the rims, but should improve the ride at 12 psi.
The X320 has Carlstar 18-7.50-8 front and AT2 6 ply 23-11-10 rear.
Lots of room on the Kubota for a #3600 filter, but the bigger OD PH8A size won’t go on because there’s a oil pressure sender in the way.
All my pull toys have 2 inch receivers, so I drilled a half inch hole into a 2 inch drop receiver and bolted it upside down to the bumper so it’s now a 2 inch riser with a two inch ball.