omc A motor

[calvin]

Thanks f or the tips I will take my time and go over it totally. It was raced in the salt for a while.

[champ20B]

Thanks f or the tips I will take my time and go over it totally. It was raced in the salt for a while.

Your welcome! I enjoy helping enthusiast with any tips I can. One more thing I thought of when I saw that it was run in salt water was the tuned exhaust pipe inside the mid-section (tower) of your engine. When you pull the power-head from the mid-section, remove the tuned megaphone pipe. Check it for any corrosion damage. This is a simple horn shaped pipe that can be patched with welding. Often times, this part can be found on e-bay. What this component does is boost your engine's power via the process of deflecting sound waves from the exhaust as to pull extra air/fuel through the intake/induction of your engine all the way out through the exhaust. It then bounces the extra charge of this air/feul, that would have got away, off other existing sound waves back into the combustion chamber or cylinder. This is like a reverse super-charging effect that will increase induction and compression.If you have the 13.2 cubic inch version of the 15HP "A" racer, that is how OMC achieved so much power out of this little engine besides just having an excellent design overall. I assume that the later 15 cubic inch model had this feature as well. From what I have seen of the 13.2 cubic inch OMC, as a fishing motor at that, I can assure you that little engine had guts! The racing versions can hit 60 m.p.h from what the APBA states. You can see them on You-Tube videos on line in the "200cc modified outboard races". You'll be amazed! I remember running my Mark-25 Mercury on a 14 foot fishing boat at full throttle and seeing two guys in a equal sized boat with one of these little 15HP motors just about keeping up with me. The later 15 cubic inch version was just as good also, if that is what you have. Honestly, I believe these motors were in the 18-20 HP range in reality. Of all the engines OMC made up to 150HP, the 15 model had the best horsepower per cubic inch output ever. Let me know how it turns out when you're done restoring your engine.