So I bought a used l3901 tractor for my dad. It has over 9k hrs on it but has been deleted. I then found a used la525 to put on the tractor. Works great but after I run it for about 5 or 10 mins it starts blowing alot of blue smoke and will smoke more the harder you use it. If you shut it off for 10 mins and the fire it back up it won't smoke for a couple minutes again. I changed the oil filter in the catch can thinking it was drinking it's own oil from blow by but no it's still doing it. Do I need a new head? Is it warming up then letting oil in somewhere? I dont know where to look next. Any help would be great, I bought this so my dad could use it around his house now since he's retired. Thank you