Mercury 9.9 Lower Unit disassembly

[outbdnut2]

I’m working on a 1986 9.9 Merc for a friend. SN: 0A937746, with what I believe is the "Design 1" lower unit designation I found on the drawing at marineengine.com (no Hi-Reverse Thrust Cup behind the propnut that "Design 2" has).

It needs a seal kit – water in the gear oil.

I don’t work on many "Dark Side" motors, and after removing the prop and a metal ring that was formed to slide over the outer edge of the next part, it looked foreign to me. I know the 9.9 is a totally different motor than the 9.8 it replaced. Do I need a special tool to get the lower unit apart? If so, where can I buy one at a reasonable price? If I don’t need a tool, how does it come apart? I can see on what looks like the 2nd part in, an arrow and the word "Off" (maybe it said "ON" I don’t remember) cast into it.

Below is the diagram of it:
Dave

http://www.marineengine.com/parts/mercury_marine_parts/sn/0A937746/%20%201010206/496_190

[billw]

I did one of those years ago….As I remember, the entire bearing carrier unscrews. Normal thread direction. You do need a tool; but I made one from a piece of pipe, because I didn’t have time to wait for a tool to arrive. In the carrier, behind the seal, is a prop shaft bushing. Make sure it’s not worn out, before you take it apart, by attempting to move the prop shaft up, down and side-to-side. If it’s worn, your new seal won’t do you much good.

Long live American manufacturing!

[outbdnut2]

Bill – Thanks for the info, and the comment on the prop shaft bushing.

Dave

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