Lower unit - 2005 Mercury 9.9hp - Serial # OR066142

[brianmtsinc]

I am NOT a mechanic by any means. In fact, I am beginning to think I should not have attempted this.....

I removed the lower unit on my 2005 Mercury 9.9 to replace the impeller. It seemed easy enough. I removed the 4 bolts on the bottom and then the 1 bolt holding on the shift linkage and bushing - only accessible after dropping the lower unit a few inches. To the surprise of many, I replaced the impeller without issue, but now cannot get the lower unit back on. The issue seems to be the linkage and I am wondering if I screwed up by removing it where I did OR if I just need to keep working at it?? I am worried that I may bend the linkage if I push any harder.

Any help is greatly appreciated!!
THANK YOU!!
Brian

 

[Texasmark]

You have 3 things to line up:

Drive shaft into the bottom of the engine block: If the splines of the shaft and the position of the crankshaft are not correctly aligned, the splines will not engage and you will have approx. a 1" gap between the LU and midsection that you can't close. If the LU is in F or R you can rotate the prop as you apply slight upward pressure to the LU and when they align, the LU will easily slip on up and mate to the mid section.

Shift Shaft: A second splined interface but somewhat sloppy due to the linkage; not a hard stopping point like the drive shaft, is the shifter. The shifter is a 3 position cam for the 3 gears and it rotates to accommodate the gears. With a pair of vise grips (preferred) grasp the shift shaft...little splined shaft about 1" long sticking up at the front of the LU, and gently test it cw or ccw until it moves and find your positioning for which ever gear you select. If you had it in F or R to align your drive shaft, move it 1 notch, whichever direction it will move to put it in Neutral.

On your shifter, place the shift lever in N. With that done, the splines of the shift shaft and LU shifter spline should align.

Water tube: The outlet of the water pump is connected via a copper tube to the bottom of the block. This tube should be relative straight to straight on some engines. You can either insert it into the block first or water pump first, whichever is easier. Just ensure that you get it connected or you will have water squirting out of odd places and your powerhead will get how real fast when you start up.....if you have a pee port, it won't pee.

If you stick it in the block last it is somewhat difficult to see what you are doing. On later engines in higher horsepowers, they have now installed a bracket just above the water pump that aligns the tube and makes mating much much easier.

HTH,
Mark