Re: Mariner 150
The best way to get more horsepower is to trade it in. Understand that a 2 cycle engine has to balance a lot of things to get a decent operating range. Any one thing you do will cause something else to be less desirable, effective, etc.
For example:
bigger barrel carbs might give you a bit more on the top end, at the expense of idle quality.
Exhaust tuner, might pull the peak rpm up a bit, at the cost of idle and mid range performance.
You could cut the heads and increase compression to about 150. It'll gain you a bit more torque over the range, and of course a few more horses, at the cost of premium fuel.
Reeds usually have little to do with top end, but a set if Chris Carson fiberglass reeds does wonders for low speed performance, without costing anything at the top. The reeds all mount on a plate right behind the carbs on the V6 making them very accessible.
Carb jet sizes go with the carb model. Simply changing jets doesn't automatically give you more power. If you're peak tuning for racing, and don't mind changing jets if the weather changes by 20 degrees, you can lean up the carbs a bit for more peak performance, at the risk of a minor timing error costing you a piston or ventilating your block. (throwing a rod)
For me, mine's jetted factory fat, timed factory conservative, Glass reeds, fast enough and reliable. Improvements I've made are for reliability and utility. I discarded the "advance" module, and converted electrics to dual regulator 40 amp.
