9.9 mariner questions

Just purchased a 9.9 Mariner S/N 682C L 368082, What year make is this motor, it was made in Japan?

The Owners manual list 9.9 and 15 HP motors also same Bore, Stroke and Displacement. What is the difference?

Since mine is a 9.9hp what can I do to get the extra 5hp out of the motor?

Thanks for any help !!!

The motor was built by Yamaha and If I remember correctly, all you had to do was change the reed cage and carb.....if you can find them. That motor is probably around a 1983-84. Hope this helps!

Hi I make that a 1985.It has to to do with the crbs been rejetted/changed,reeds changed.If Graham happens on this he will give you the ins and outs and the reasons not to bother,increased fuel consumption for 1-2 mph extra, cost of parts if they can be found etc. etc..These are clones of Yamaha's older motors built for merc,painted gray and called a mariner. Please refer to my user name regarding these motors

Yes, although 5 horses sounds like alot your top speed would only increase 2 mph on a perfect day.

I have converted many a 9.9 to a 15 for guys who despite my advice to the contrary still wanted to go ahead with the upgrade (carb and whole reed cage and reeds on the Yami/Mariners - about 300 bucks in OEM parts or Carb and exhaust plate on Merc/Mariners - 250 in OEM parts).

So you have to ask yourself, is each extra 1 mph worth about 150 bucks (just in parts) - double that if I'm doing the work???

Your best bet for a performance increase is to spend the money on - waterpump service every second year, new spark plugs every year, new gear oil every year and fresh, stablized gas for each outing plus sound storage proceedures and winterization whenever the motor will not be used for 2 weeks or longer...

Should have added the one performance increase that does occur -

The MENTAL performance increase.

You have MORE horses so you THINK the motor is now "bigger, stronger, faster".

As long as you don't compare the pre-retrofit motor to the post with a GPS and Floscan the illusion is maintained...

Forgot to add (getting old)

If you live in the US it is ILLEGAL to alter the horsepower on an outboard (unless it is being used for racing purposes and you belong to all the right organizations).

Here's the blurb directly from Merc to it's (techs) - being in Canada it doesn't apply up here, but for our southern neighbours -

"
EPA regulations prohibit changes to engines that could affect emissions limits. Per the service manual, "The dealer and/or consumer is not to modify the engine in any manner that would alter the horsepower or allow emission levels to exceed their predetermined factory specifications." The only changes permitted are carburetor jet and gearcase/gear ratio changes for high altitude operation as detailed in applicable Mercury Marine Service Manuals."