150 JOHNSONS VS 175 JOHNSON

[JTM]

WHAT IS THE DIFFERENCE IN A 150 AND A 175 JOHNSON'S 2000 MODS. THEY ARE THE SAME CUBIC INCHES BLOCKS. WHAT IS OMC CHANGING TO GET THE EXTRA 25 HORSE POWER. IS IT BIGGER EXHAUST PORTS OR BIGGER CARBURETORS. THE REASON FOR ASKING IS THAT I'M REBUILDING MY 150 MOTOR, TRYING TO GET A LITTLE EXTRA POWER OUT OF MY MOTOR. THANK YOU FOR YOUR TIME.

 

[blanchy]

Re: 150 JOHNSONS VS 175 JOHNSON

If you get a reasonable answer, please tell me. I want to do the same to my 40

 

[JB]

Re: 150 JOHNSONS VS 175 JOHNSON

JTM and Blanchy, OMC's favorite way of adjusting an assembly to the HP they wanted was exhaust tuning. They often also used larger throated carbs, different reeds, higher compression, different port sizes and different port timing. <br /><br />The bottom line almost always comes out that it is less expensive to trade the whole assembly than to swap parts.<br /><br />If you come upon a junk 50, Blanchy, or 175, JTM, it might be worth the trouble to swap key parts. Otherwise I recommend you look for more speed by fine tuning your prop and boat, rather than your engine.<br /><br />Red sky at night. . .<br />JB