Northwest Fishing Reports

I've seen comments about hp. conversions I have a 2006 Merc 4 stroke Ls. What is involved ,the costs ?, and does it really
work out ok. My 9.9 just cant quite put my 2013, 12' Smoker craft Alaskan on plain, I have done every thing I can to
balance the weight, It is rated for 15hp. Please give me some pointers, I would love to learn more.

Thanks , Fred

Here is a link to what you are looking for:http://www.cruisersforum.com/forums/f54 ... -6396.html

Before you start down this path, you may want to check that the pitch on your prop is right for the boat/load it is trying to push.

You also want to make sure the 2-stroke discussion in that link applies to your 4-stroke. I don't believe it does.

Your 9.9 shares the same engine platform as the 8hp, not the 15. The 9.9 displacement is 12.8ci, the 15 is 21.4ci, and the lower unit gear ratios are not the same either - http://www.mercurymarine.com/compare/ou ... mpare=7,10" onclick="window.open(this.href);return false;

More research might save you a big disappointment after dropping $300 - $400 for a new carb only to find your motor doesn't perform any better, and possibly worse, than it did before.

Although many four stroke OB's have common blocks with in size ranges, I wouldn't even begin to consider trying to hotrod or convert one to a higher hp model. Chances are there is a lot more to switch than just a carb. To get more HP you could have to change the carb or injection, the cam, the head/intake, pistons and in some case the exhaust. We aren't talking old two strokes here. If you can't get it to plane with a prop change pony up and buy a new motor. You would probably spend more on parts than you would for a new motor.

I have a 2006 Merc 9.9 2-stroke convered to a 15 HP and its great. but I do not think you can conver a 4- stroke.

I installed the 15 hp carb. and exhaust system that it.