9.9 to 15 conversion...Merc.

[RIDEPATE]

2-stroke. 0D267077. 1993. I've done a lot of searching with what I would say not the greatest results. I do know I have a WMC 46 carb and that I need a WMC49 (15 h.p.) carb. At first I thought I'd only need to up the main-jet from a .056 to .066, but after seeing pics of the carb inlet openings, the 15 carb has a lot bigger "hole" on the inlet side, which would make sense. The exhaust-plate, or tube is larger on the 15 also. I cannot find the correct PN#s for the 15. Anybody done this conversion??
My reasoning for the conversion is we have been having some serious fun racing Jons. Just a small group of 5 of us so-far. We call ourselves the GJBRA, "Georgia Jon-Boat Racing Association" lol... We have traded-paint and have had one barrel-roll....Our rules are 15 H.P max. A 10footer with a 15 Rude has been owning the course, if he don't blow the turns, his turns are ugly.....My lightweight, 111#, Tracker 12-footer with the current 9.9 rails the turns, but "Mr. Rude" ,if he don't blow a turn, gets too far out for any of us to catch. Most fun I've had at 20MPH in a long time. It's time to be a sleeper......What parts do I need???

 

[ondarvr]

Re: 9.9 to 15 conversion...Merc.

Jets alone are never the difference, they are only different because other parts are different.

I was looking at the chart the other day and I thought it was in 94' when they changed (upped) the displacement of the 9.9 to the same as the 15.

 

[ondarvr]

Re: 9.9 to 15 conversion...Merc.

I looked at the manual again, it says 95' was the year they changed the 9.9 to the same displacement as the 15.

 

[RIDEPATE]

Re: 9.9 to 15 conversion...Merc.

The 93 has the same case, bore, pistons ect as the 15. I'm looking for part#s and someone who has actually done the conversion.

 

[ondarvr]

Re: 9.9 to 15 conversion...Merc.

Here is the link to the sticky at the top of the page, go to page 1A-2 it will have the specs for the 6 through 15 hp motors from those years.

Boatinfo - Mercury Service Manual for 6-8-9,9-10-15 hp

 

[MH Hawker]

Re: 9.9 to 15 conversion...Merc.

I did it on a 96 over the winter and its working fine, but I changed the carb due to the venturi effect differences as well as the jet, but from the research I did the break point was 95. Their is a good bit of difference on the ramp piece that opens the carb up and a link and a sink is also needed.