Just bought an 1986 25hp tiller Merc for the ole Jon boat. Suspected junk in the water jacket and wound up finding a mud dobber nest right at the cooling water outflow in the jacket (would have been a big disaster if started). Anyhow, I am able to take a look at the rings, pistons and cylinder walls since the inspection covers are off. There is a little carbon on the cylinder heads that I can see. Should I try and spray some sort of carbon remover on them (and the rings at the same time) and knock it off? Suggestons on spray? Also, should I be able to see trauma/scoring/scraping to the cylinder walls (if it is there) from this perspective? What should worn out rings look like (would I be able to tell?) Thanks for your suggestions and advice.
