Re: 100HP Evinrude
100193 is a 1971. To confirm, that should be an hydroelectric shift, with thru-prop exhaust, right?<br /><br />Regarding the bad cylinder, whether to replace or repair depends on a lot of things. <br /><br />1) If you're looking for inexpensive, non-critical use, you may be OK sticking with it. SOME 2stroke outboards die very slowly after scoring a cylinder. If the motor is still running reasonably well, you might stick with it. Fix whatever made the cylinder go bad in the first place (gummed up carb, timing too far advanced?), back off the timing 3 degrees, & keep running it.<br /><br />2) If the motor's real clean (no salt water corrosion so it's easy to take apart), you may be able to find an inexpensive used powerhead. Any 1969-72 OMC V4 will bolt on - the ignition would be the only difference. The gearbox & powerpacks are sometimes expensive to replace, leading to people selling good powerheads fairly inexpensively.