i dont have the modle number on me I will get it and let you know. I have had this thing for 7yrs and i dont cut anywhere near the amount of site that i did when i first got it. i thought the lifter as well after reading a few threads. i just had the oil changed because i over filled it a few weeks ago. i over filled it because It started ticking on me while i was cutting. I was not think about how much oil I put in. I did not check the oil when i got it out the shop last week. i only work on the weekend now so this morning before i headed out I checked the oil. those shop guys did not even fill the thing to the correct level. I was also missing a nut on the right side exahust manifold. I thought that would solve the problem. It did run a lot better today. I cut maybe six ac today. It started ticking on the first lawn but it was not near as loud as it was last weekend but it was still very faint but i noticed it more when i cut on a slope. i guess i will take it back to the shop and let them look at the lifters. how hard is it to change the lifter? do they have to remove the engine? thanks for replying.