# mercury sea pro 25 hp



## flyingstretch (May 25, 2011)

just baught a brand new 2009 merc seapro 25 HP still in break in period, like railroader said, ildes rough, but WOT is strong and very smooth.....i love it, previously had 4 stroke 15 HP and not aloud louder.


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## Marathon75 (Apr 14, 2011)

I just took mine out this am to start my break-in period too...you are right about the rough idle, but just a slight crack of the throttle smoothes it out.
I ordered the electric start kit for mine, should have it in next week. Bought the $6.95 carb gasket to convert it to 30 hp, but will wait to install until after break-in.
Made a brief foray for just a couple seconds at close WOT after running for an hour or so, gps said 30.6 mph!
I think I will enjoy this engine for many years....


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## flyingstretch (May 25, 2011)

Did you mention that just the carb gasket turns it into a 30HP, ive been checking to find out which part(s) where diffrent in the two motors, and had yet to find anything! how did this info get to you? i would very much like to upgrade my 25hp

thanks

MArc


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## flyingstretch (May 25, 2011)

Just when back and checked on Usboat supply, and from what i could see, is that the 25HP has and extra restrictor gasket between carb and reed block, would just removing and replacing this gasket do the trick?

thanks

Marc


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## Marathon75 (Apr 14, 2011)

That's basically all that's needed, although you should advance the timing 5 degrees from 20 to 25 degrees BTDC. Take a look here:http://www.rib.net/forum/f36/uprating-mariner-25-to-30-hp-part-2-a-25933.html.
The 25 hp Restrictor Plate has a significantly smaller cross-sectional dimension vs. The 30 hp, which is just a standard gasket.
Curiously, my engine was already set at 25 degrees BTDC. It's a simple, "static" adjustment that takes only a minute to perform.
I'll gps mine in both "25 hp trim" and then again in "30 hp trim" with the same load to see if there is much difference....expect to pick up perhaps 1-2 mph?


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## Cody_F (Oct 26, 2010)

where did you get the motor from


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## mark_gardner (Mar 18, 2009)

> That's basically all that's needed, although you should advance the timing 5 degrees from 20 to 25 degrees BTDC. Take a look here:http://www.rib.net/forum/f36/uprating-mariner-25-to-30-hp-part-2-a-25933.html.
> The 25 hp Restrictor Plate has a significantly smaller cross-sectional dimension vs. The 30 hp, which is just a standard gasket.
> Curiously, my engine was already set at 25 degrees BTDC. It's a simple, "static" adjustment that takes only a minute to perform.
> I'll gps mine in both "25 hp trim" and then again in "30 hp trim" with the same load to see if there is much difference....expect to pick up perhaps 1-2 mph?



please keep us posted on what becomes of this, i'm very interested in knowing


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## Guest (May 28, 2011)

> > That's basically all that's needed, although you should advance the timing 5 degrees from 20 to 25 degrees BTDC. Take a look here:http://www.rib.net/forum/f36/uprating-mariner-25-to-30-hp-part-2-a-25933.html.
> > The 25 hp Restrictor Plate has a significantly smaller cross-sectional dimension vs. The 30 hp, which is just a standard gasket.
> > Curiously, my engine was already set at 25 degrees BTDC. It's a simple, "static" adjustment that takes only a minute to perform.
> > I'll gps mine in both "25 hp trim" and then again in "30 hp trim" with the same load to see if there is much difference....expect to pick up perhaps 1-2 mph?
> ...



Smalloutboards.com

They come from Canada via Japan
they are new, but based on a 1996 Tohatsu and the only difference between the 25hp and 30hp is the carb gasket

$2900 shipped to your house


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## flyingstretch (May 25, 2011)

Pulled the cover on my motor today, mine was also already set to 25 degrees, and the carb is fully opened at WOT. i guess now all i need is the gasket, i will also wait till break in is done before i move ahead with mod! i to will post performance before and after the mod!

marc
14" inflatable 25 HP Sea Max Mercury


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## flyingstretch (May 25, 2011)

HollicaSnooze, how much did the electric start kit set you back? and where did you buy it from?

thanks

Marc


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## Marathon75 (Apr 14, 2011)

I paid $490.00 for mine from my local prop guy, (bospropeller.com)....he sells Nissans here in Louisiana.


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