ENGINE TROUBLE on YZ5700

[jbird]

Start up is fine, then while cutting the engine will SOMETIMES change sound and it will lose power almost like it is only firing on one side. If I shut it off for 20 minutes it will be fine again. It doesn't always do this but usually once every cutting (one acre). I tried changing spark plugs a number of times with no results. Someone told me it might be the coil. If so how much? Also I need wheels for the mower deck!!!
Hope someone can help!

[YamahaGenuineParts.com]

Hello ...On your YT5700 Tractor, you should check to ensure both the intake and exhaust are not restricted, I have encountered a bees nest in the exhaust outlet on my own machine which caused the tractor to wheez like an old man and run poorly after 15-20 minutes run time, would not climb hills or operate the mower deck.after that I would start to look at other things.
The mower deck wheels are $32.36 ea and are available, shipping would depend on quantity ordered.
Regards
Speedy

[jbird]

thanks for the response . But if that were the case why doesn't it do it every time? I will check it out today anyway.