Am I getting in over my head? I have the Mercury manuals and have done work on automotive engines however I know outboards are a beast of their ownÂ…
BlackMax impellers are easy, IMO.
I don't know about an experienced mechanic taking a couple of hours. I can do it in 30~45 minutes.
The important thing to remember is never twist the shaft the opposite way of the engine because you'll fold the impeller blades backward. Apparently this can be a problem although I've never had cause to test turn it the other way to see what damage would happen to the rubber.
It sounds like a job you will have little trouble with. The difficult part is getting the damn gear case back on the mid section. It can be a real pain. I've spent 30 minutes trying to get one on. Put the boat in neutral and don't move the stick or twist the shift shaft when the gear case is off and you'll be fine. The shift linkage connects first, then the drive shaft. If the drive shaft baulks, you may have to get someone to twist the flywheel a few degrees to get the splines to line up while you push the LU into place.
Once you've done it once, it will be no big deal.
Oh yeah... don't forget the front stud is a little bigger than the rest and will take a different nut. Keep the little tabbed washer and nut from the front stud seperate. The rear bolt is under the turn fin so you have to remove the turn fin (or cover plate if you've deleted the turn fin) to get at it.
One last thing... it has been recommended to me to always replace the entire housing with a housing kit. The kit comes with impeller, housing, gaskets, etc. I've replaced just the impeller before and it was fine but it's only about 10 bucks more for the whole kit.
- Tom