Suzuki DT15 Performance Improvement

I have an old but lively 1986 15hp Suzuki DT15. The maximum hp/rpm for the stock engine is 15 at <br />5500 with a 9x11 prop. The displacement of this engine is fairly large for a 15 hp. I think its around 287 cc. I know that the older Johnsons and E-rudes 15s were only 216 cc. but made their maximum power at around 7500 rpm. What I would like to know is how can I make more rpm/hp without going to a smaller prop? Is there anyway to adjust a governor or something to allow the engine to spin higher and would there be an issue with reliability if I can get 7000 rpm out of it? The engine performs fairly well as it is. I have a Humminbird XT400 with a speedo that wildly indicates 32 mph. I used a gps wich showed maximum speed of 23 mph. Is there any fix for speedo error on the XT400?<br /><br />Any info you can provide will be greatly appreciated.

Re: Suzuki DT15 Performance Improvement

You could modify the intake and exhaust porting. You could cast a new exhaust header in aluminum. You could design, develop and cast a new intake manifold and reed block. Once you did this you could add a larger carburetor. Now you will need to put in new wrist pin and crank bearings to handle the higher rpm. OR for 1/10 of this price you could purchase a new 25 hp outboard with a 3 year warranty.

Re: Suzuki DT15 Performance Improvement

Thanks LT. That's not exactly what I'm after. I'd just like to squeeze as much power out of the engine without major mods. Is there no way minor gains can be made from simple things like carb jetting, fuel enhancers and timing?

Re: Suzuki DT15 Performance Improvement

Timing is probably optimum if its factory spec. Danger of preignition in 2-strokes if too far advanced. Rejetting a carb will not gain power unless a Bubba has mis-jetted it away from factory specs trying to cure a broken engine. Make sure your engine is running properly. Put a can of decarb down the carb throats. Invest in a tachometer, and make sure the engine is on top of its power curve (probably at least 5500 rpm) and experiment with raising the engine and maybe a different prop.