I just purchased another project (like I need another one!). I thought it was a Mercury 200 hp outboard but found out that although the leg and engine cover is from a 1989 Mercury Black Max the engine block is a 1990 Mariner 150HP,I know this because of the serial numbers. I am pretty sure the power head is made of a combination of different engine parts due to the appearance of some of the parts. The block has been bored .015 over and looks fresh (no carbon build-up and clean bores)but the heads look like they may have some time on them (some salt in the cooling passages). My question is can anyone tell me what heads I have from the casting numbers? The number on the heads is 18787-C2. Sorry for the long lead to this question.<br />PS. I may be asking about the carbs in the future. I am in the process of tearing down the engine for inspection and rebuild if it is worth it.