1998 Mercury 9.9 prop parts

[riverkeg]

Hello iboat folks. I recently acquired this motor and I noticed the prop would slide back and forth on shaft so I looked online for the parts that are supposed to be there and I noticed it was missing (or so I think) a spacer. With the other parts, there is only 1 way I found that they would go together. In this order, from the prop, is the spacer, the reverse exhaust block (cone shaped part), and then the prop nut. I took the boat out this weekend and it didn't want to pump water so I shut it off (it's not the primary motor). When I test ran it on the boat prior to this change, it pumped water just fine so I think this has something to do with it. Plus, adding the spacer makes the exhaust block stick out pretty far and it doesn't look right. If you look at the picture, one could say I'm supposed to use the spacer (item 60) or the exhaust block (item 63) but not both. Any help?

 

[riverkeg]

Re: 1998 Mercury 9.9 prop parts

FYI - I found the answer after some extensive internet searches. It turns out it is an either/or situation. That cone or cup shaped part is used to help reverse performance and the prop movement is intentional to allow the exhaust gases to escape ahead of the prop which improves the bite of the prop in reverse. Since I will be using the motor for backtrolling, I'll take the spacer out and test the water flow again. I'm not sure how, or if, it affected the cooling water suction so if that doesn't do it, I'll need to do an impeller change. Just thought I'd pass this information along to someone else that might need it. Happy Boating!