679cc efi engine
 

My efi engine wont get up to speed. It sounds ok at first but when i engage the mower it bogs right down and sounds terrible. I check all pulleys on deck and everything is turning with no resistance. I installed new spark plugs and replaced air filter. Any help would be great before i haul it off to dealer. The motor has 200 hours on it

What model tractor/zt and make of engine are we working on?

For starters, I'm looking at fuel supply ( fuel filter?) Or a cylinder down (missing spark?)

fixed I hope
 

Its a mtd 679cc efi on a cub cadet slx 50 xt2 tractor. I readjusted the spark plug gap. The manual says a range from .025 to .031. I was at .025 and changed it to the wider end .031. Seems like the computer likes that gap better and runs like new. Thank you