Re: 1987 9.9 Merc powerhead replacement options
Joe,
Did the same thing this last summer on a 1999 25hp Merc. I would suggest contacting a firm out of Tennessee by the name of MARFAB. I spoke to a gentleman by the name of Kurt (I believe thats right). Anyway he was very polite and knowledgeable. Yes, you can purchase a new powerhead but they are somewhat on the expensive side
MARFAB will rebore your cylinders for a nominal charge and they also sell the pistons and rings as well. I was also told that some shops will "short block" it for you where they bore the cylinders, install the new pistons/rings and reassemble the two halves of the block - all for a nominal charge of course. Marfab may do this as well -I'm not sure.
I did the work myself and to be honest I had a few nervous moments but overall it wasn't as bad as I thought it would be and the motor now runs great!
First and FOREMOST - get an authentis MERCURY Service Manual for your specific motor. Pick up a good torque wrench and a bottle of Mercury 2-4-C with teflon as well as some loctite master gasket. The first problem you will run into is the removal of the flywheel. My local Merc dealer lent me their tool to use - you may want to look into that ahead of time you will also need a strap wrench to grip the flywheel. Beyond that most common tools will take care of the rest.
Photograph every step of the disassembly process BEFORE removing the part - you will be glad you did during the reassembly process. I laid all of the parts out on a long table in the order they were removed. I also labeled each part and groups of bolts/nuts/etc. with freezer tape and a marking pin. It's amazing how much you'll forget in the week-two week period before reassembly.
If you decide you want to give it a try feel free to PM on this site and I'll help you if I can - I'm no expert but I know alot more about 2S motors now than I did a year ago.
Good Luck.
