Reference the link below for parts page.
Item 11 is the prop shaft holder assembly. I think it would be pretty near impossible to replace those seals (#25) (note that there are two of them "stacked front to front") without first removing the prop shaft (#29) from the holder. In order to do that, you will need to take the holder out of the gearcase. Item # 18 (washer, claw) is a locking device used to retain item # 7 (nut, gear case end) and keep it from backing out. That nut is where the special tool comes in. You need to locate and "unbend" the tabs on the washer so that the nut can be turned and then turn the nut with the special "inside spanner" socket (about $80). I have removed them from other brands of outboards with a hammer and punch, not having the tool, but never on a Honda.
http://www.boats.net/parts/search/Honda/Outboard Engine/1997/BF45AM LRTA /PROPELLER/parts.html
The problem is that, in many, many cases, the nut and the washer are both bonded to the gear housing due to corrosion and, with the tool or without, they sometimes come out in pieces themselves. If you decide to attempt this repair yourself, make sure you soak the items in PB-BLASTER for a day or two before getting started and plan on replacing them both at the outset. IT IS IMPERATIVE THAT YOU USE EXTREME CAUTION TO NOT DAMAGE THE THREADS FOR THAT NUT ON THE GEAR CASE. If you damage those threads, you're done and will need a new case.
Then, there is the seal itself. A REAL PAIN! These can be a booger bear to get out without damaging the housing and seal boss and can be just as stubborn about going in straight and true without deforming. There are also special "seal installer" tools that most serious mechanics have for doing jobs like this. The first timer would be wise to have more than one replacement seal on hand in the event of "accidents". One way to make this job go much easier and get a reliable outcome is to just buy #11, the prop shaft holder assembly.
AND THEN...when you get it all together, it NEEDS to be tested. LET ME SAY THAT TO YOU AGAIN. IT NEEDS....NO.......IT ABSOLUTELY NEEDS TO BE TESTED.
More special tools. It is REQUIRED that you pressure test and then vacuum test the gearcase to make sure it will NOT leak. If it does not hold a slight pressure or a partial vacuum, then it will leak in service, water will enter the transmission, and you will destroy your lower end in short order.
This job is best left to a pro that has the tools and the expertise to do it right. But, if you can't afford to pay someone to fix it, then make darn sure that you at least check the gear oil for water intrusion every time you use the outboard for the first few times.
As far as the grease goes, marine grease is pretty much available at most auto parts stores so why not get some? Grease is lubricant (usually oil) suspended in a semi-solid, usually a fibrous soap. The soap is formulated from different substances that will have resistance to it breaking down in specific environments and allowing the lubricant to flow away from the component it is protecting. Marine grease is specifically formulated to not wash away in salt water. That is why it is specified for outboards.
Good luck with your project.
