Impeller replacement on 2-stroke Merc 3.3

M

matt_unique

New member
Well my final project for the week was to tackle the impeller replacement on my 2-stroke Merc 3.3 outboard.

A rep at the Merc dealership was kind enough to provide me with photocopies of the lower unit schematics. I thought about buying the service manual but decided to give it a go with just the schematics and other non-specific references I found online.

The most time consuming part was scraping the old gaskets off the stainless steel parts. For the impeller replacement there are two gaskets that must be replaced in addition to the actual impeller. Once done there was some effort required to get all the tiny parts back together and aligned. It took me a few hours but the job went well.

If anyone is considering the same maintenance on a similar engine I'm happy to share the tips/tricks I learned along the way. I immediately made good notes to make the next one go more quickly and easily.
 
I just finished doing the same on my 3.9 Merc....had a terrible time getting everything lined up when I put it back together.... finally used a bit of plastic tube to line everything up....and once together the tube will just ride on the outside of the cooling pipe...that slip fit was miserable..

Joel
SEA3PO
 
The most time consuming thing for me was cleaning off the gasket remnants that stuck to the metal.

The 2nd most challenging was definitely getting the lower unit shaft back into the engine. I had to engage the prop and spin the prop a bit until it would slide back in.

It definitely helps to have the entire engine mounted on a work bench for easier access.

Beats paying the $110 p/hour shop rate!
 
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