If you're concerned about compression, do a leak-down test and check your fuel system, especially if you have one of the cheap fuel regulators. I had one that had a leaky diaphragm that ended up with approx 1 qrt of race fuel in my crankcase. The day before going to a test session I had a very hard start and even though I kept smelling gas, I hadn't done basic inspection (look down the throttle bores with the electric pump running) and almost hydrauliced (sic?) a cylinder. The next day I noticed bubbles coming out of the front corner of the oil pan (crankcase pressure) and oil on the trailer deck! So much for that test session, back to the shop! The following day I drained the oil and noticed not only the strong odor of fuel but it was also diluted with gas in the oil pan; glad I didn't make any passes on that fresh engine! Needless to say, I pulled the engine and discovered washed bearings, scuffed cylinder walls but saved myself a big bill from catastrophic engine failure...it's always the little things. Not saying anything about your situation other than, make sure of what you do know so it doesn't bite you!