Actually, I do know how engines work. I merely said I am no expert. I don't know all the nitty gritty about each part in the assembly. Back in my college days and shortly thereafter, I had no money to pay a mechanic, so I had to do my own vehicle repair. In addition to changing oil and replacing spark plugs, I repaired starters, replaced head gaskets, replaced carburetors, adjusted valve tappets, installed headers and a few other things. I did not like doing it, so as my career advanced, I was able to pay others to do it. I still have to change oil on my ZTR, and I had to do oil changes and an exhaust manifold job on a Kubota tractor. These days I don't even do that on my Mahindra tractor, as my neck hurts from working under a tractor. I don't do any work on breaking down my chainsaw engines. I expect my MS500i will outlast me at this point, so all I need to do is sharpen the chain as needed and replace it when worn out.