[MaGuyver]

Has anyone changed a water pump/impeller themselves on a Yamaha 90 4-stroke? If so, how hard is it? Do I need the manual? Should I just let the dealer do it?

 

[TwoKids]

Never done an F90 but have done a yammie 150 hpdi many a times.  Overall not difficult (<1 hr), toughest part on mine is the impeller woodruff key gets stuck in the shaft sometimes. If penetrating oil and brute force doesn't break it loose than a dremel with small thin wheel does the trick. Just be carful not to dremel to deep such that you get into the shaft. Also be sure you lightly grease the housing and set the fins in the correct direction when you mate the housing with the impeller.  I buy my parts from SIM Yamaha, great folk great prices. If you call them Andy Jr will give you some tips on your specific motor. Prob lots of vids on youtube as well. Good luck.

 

[MaGuyver]

Thanks.
I just found some videos. It does not look that hard.

 

[hferrell87]

Changed mine for the first time about 4 months ago and just watched a video on youtube. I have a Yamaha 70 2 stroke, but I wouldn't imagine the impeller/water pump would be any different for your four-stroke. I just took my time and took a picture of every step that I did (as a fail safe).

While you have the lower unit dropped, take the time and really look at everything. Grease all the splines and other areas that need grease. While the prop is off, go ahead and regrease the prop shaft too!

https://www.youtube.com/watch?v=W3sr6El4rh0

This is the video that I followed, but did have a couple different gaskets than his, but all in all, very easy to do.

 

[MaGuyver]

Any thoughts on engine and lower unit oil? Are there better oils out there than what Yamaha uses?

 

[hferrell87]

Any thoughts on engine and lower unit oil? Are there better oils out there than what Yamaha uses?

Not in my opinion... I always stick with Yamalube products to ensure its getting what it needs per spec. Other brands will work fine i'm sure, but I always try to go verbatim with what's recommended by the manufacturer.

At the least, make sure your engine oil is TC-W3 certified and foot oil is of good quality...

 

[hferrell87]

http://www.boats.net/

BTW, I use this site to order all my OEM parts when doing the lower unit service or any other repair/replace. They have numerous diagrams and allows for easy understanding of what is involved with each part.

 

[MaGuyver]

Nice site.