MF 135 bogging down issue.
I have a 1974 MF 135 Perkins 47 HP 3 cly gasser. Yesterday as I was bush hogging I ran out of gas, after filling tank and resuming work my tractor began to really struggle going up hill to the point that I had to quit and try and make it back to the barn. The tractor was idling and reving fine but was getting some backfiring out exhaust. Have not pulled the sparkplugs (yet). I did check fuel flow and it is very strong to the carb. She fires right up too.
My question is does it sound like a fouled plug that could be the culprit to the loss of torque / power? any help guidance would be greatly appreciated.