I'm going through my tech manual and it tells me how to determine TDC from my number one cylinder. I have a 1990 90 Hp Johnson VJ90LESB. But, I have had my flywheel off to replace my rectifier/voltage regulator and there is a key that locks in the clocking of my flywheel. So, I'm thinking that TDC is set at the factory. Am I safe to assume that TDC is correct, or should I get a dial indicator and measure it myself?