They ended up pulling the head and finding a hairline crack in the intake valve area for the cylinder closest to the seat. Been there since day one and and got worse the more hours I put on the machine that is why it would run great when cold and the warmer it got the weaker it got. Final started to pulse the air filter and shop decide they need to pull the head and find out what was wrong even though kubota did not tell them they could. Kubota refuse to to admit they had a head problem until they saw the crack. Long story short replaced the head and it runs great, althought it did need the valves readjusted after about 50 hours on the new head. Got nine hundred hours on it now and i love it, but I still worry about because of all the problem early on. With the filter thing we change th filter to a spin on one from on of the larger tractors and it work alot better than those plastice inline ones. ordered the whole housing and bracket off a 50 or 60 hp tractor and made it fit, Alot of the ones around hear are all running the spin on ones now because the are alot better and you do not need to change them as much.