Originally Posted by
champ20B
This reminds me of the 3hp class that I think the AOMC did. I found out about it and, just for fun, built a 12ft plywood jon boat and fixed up a little 3.5 Chrysler. Once I climbed to the middle of the boat under way and with a longer piece of pipe for the handle, this little boat would really scat!! I'd say about 15-18mph (darn good for a 3-1/2 hp).
There is also the Zephyr racing. These are race boats that are equipped with the (antique) rotary valve opposed 4-cylinder evinrude zephyr, rated at 5.4 hp.... These are about 10 c.i.d with aluminum rods like the evinrude light-four 9.7hp, but only smaller. I had one of these that I bought for fifty dollars while I was in high school. The motor was about 50 years old, and everyone said I would never get it running. The ignition was rotted though the rest of the engine was well preserved. My dad proved them all wrong! He taught me how to put later style coils on the old style coil-heels. It took two later style omc coils on each heel wired to fire two cylinders at once alternately. It worked!!
After that we took a carburetor from a 12hp Chrysler outboard, and made a split intake tunnel ram manifold. (the zephyr had a two barrel type carb so we made a one barrel to two manifold from 3/4" tubing.) Once I put that on the boat and ran it like I did the 3.5hp, that zephyr was fast as heck!! It would run as fast as any 10hp fishing motor!!
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