90A impeller change

[OsoGrande]

Any ideas where I could find an exploded parts view or detailed description of the process to change out an impeller on my 90 hp Nissan? I'm fairly mechanically inclined, but more on vehicles/ bikes. Thanks for any suggestions

Also, while we're at it, prop size/ pitch suggestions? It's an older Mako hull, and holeshot isn't such an issue at this point. However, boat currently runs 25 mph @ 4K rpm, and still 25 @ WOT (5.5K). Current prop is a 14-K, I'm assuming 14" dia., maybe the K is a code for pitch?

Thanks,

Paul

 

[pvanv]

Re: 90A impeller change

I always recommend a wp kit (as opposed to just the impeller), as it lasts a lot longer, and pumps better. Both the parts catalogs (available from a lot of sites online for free) and the Factory service manual (copyrighted, so not available online) show great diagrams. For a video of the process (albeit on a Merc 90 hp motor -- with slightly different systems), see http://www.youtube.com/watch?v=BiQNhFYFvdQ

There are some differences among ob brands:
- The Tohatsu wp kit comes complete with a new ss cup, which that particular video does not show.
- Likewise, the video mentions lubricating the impeller with grease for initial startup. We don't recommend that, for 2 reasons: 1, anything in the wp assembly is going to be pushed into the cooling system; 2, any grease may attack the rubber impeller, softening and weakening it.
- The Tohatsu pumps do not require any sealants when installing a kit.
- Different brands have different shifter setups. Tohatsu uses a brass coupler with ss roll pins, which is quite different from the Merc in the video.