WTB 15-25hp outboard short shaft / racing lower.

[Pitchfork]

Looking for a short shaft outboard Merc 25SS for an 11' hydroplane. Have setup with deadman's throttle already. Somewhat local pickup. I'm in SE Michigan.

[ZUL8TR]

Try here https://johnsoldmercurysite.com/phpBB3/index.php requires membership for complete viewing, $15/year

[Steve14D]

I have the Evinrude 25HP powerhead on a Wizard lower unit that has the same gears as a 25SS but not the streamlined gearfoot and doesn't need a greasing tool. I had a 25SS for years and while the Evinrude doesn't have the top end it sure accelerates much better. I work in Coldwater MI and live SE of it.

[ZUL8TR]

That service set up will accelerate better because you have a larger service prop not the smaller quicki 16:21 prop that the race 25ss uses. That Wizard tower is also longer than the 25ss tower. What ever works for you is fine.

[Steve14D]

I am using sleeved D props and on the Hydro I used to have it would get 60 MPH+. I used the same powerhead on a A-B lower unit sometimes and would get 65 MPH on the same boat. Also used the powerhead on a KE7 lower unit with B props for 16:21 gears and would 60 MPH tops.

[ZUL8TR]

With that long service tower and stub gear case how high did you jack up the engine to get 60? On my stock 1972 25ss on the Avatar hydro stock with quicki tower and 16:21 quicki gear case to get the mid 60's with the prop shaft center near 1/2" below bottom transom height needs to be 16.5" .

[Pitchfork]

Sorry, I have been away from the computer! Been busy at work. I'm gonna do some research.
SteveD14 is the engine for sale? Do you have any pictures of it?

[ZUL8TR]

It is listed here for sale

https://hydroracer.net/forums/forum/...-unit-outboard

[Steve14D]

It is listed on Hydroracer and has a couple of picture look for
Evinrude 25HP Power head on Mercury Highspeed lower unit Outboard

[Pitchfork]

Cool - Thanks guys!

[Steve14D]

My Bezoat was built for the 25xs in 84 or 85 with the real short lower unit but the previous owner raced Yamato 20ssh and made a bolted on transom extension for it that made it easy to adjust the height. I raced it with the Yamato 80 and 102 and used a 25SS and a 30H on it at AOMCI meets and on the lake I lived on along with this motor. So I think if I remember correctly I had the transom at 16" and shimmed it from there and on this motor I switched the clamp bracket with a Mercury lower unit that had a deeper U so I could jack it up more so I would have to change my transom height. I think I usually had this motor shimmed close to 18" as going higher I didn't get anymore speed. Might have got another mile or two with higher pitch prop and shimming higher but didn't have many D propellers.