I removed the heads on my '85 Merc. 150 Black Max in order to address stripped spark plug threads only to find scoring in the walls of the no. 2 cylinder (top cylinder, port side on a V6). My belief is the damage has been there a while as there is no evidence of aluminum shavings/pieces in the cylinder. The other five cylinders are in great shape; I can still see the cross hatch pattern. Im not sure what may have caused this situation. It doesn't overheat, oil injection is working properly, etc. The motor has run great since I got it three years ago and a compression test prior to the head removal didnt reveal any potential problems. Just this year, I rebuilt the carburetors and fuel pump. The motor is also in great shape cosmetically with the exception of the standard paint scraped off the skeg of the lower unit. <br /><br />So, now for your suggestions. With a second child on the way, Im on a very limited budget. A new motor is almost certainly out of the question. Im very good with tools and I now my way around a garage, but honestly, Ive never attempted a rebuild of any type of motor. With the help of a factory shop manual, is this something that I could possibly accomplish on my own? Im not afraid of it by any means. Honing of the cylinders isn't going to cut so boring is in order I think. What's the max you can bore Merc's 2.0 V6 block? What other, if any mods, will I need to make to accomodate the larger combustion chambers? <br /><br />Sure, purchasing a rebuilt powerhead has its advantages (warranty, ease), but seems like $3000 is A LOT!! Buying a rebuilt motor has advantages/disadvantages as does buying a used motor. I guess it all depends on where you get it from. I figure by rebuilding the powerhead myself, I can save enough to be able to replace all or most of the electronic components.<br /><br />What do you all think? <br /><br />Thanks for the advice.
