I have a 1989 3hp Johnson Outboard on a 12ft aluminum boat. When the motor is at full throttle, the power is only half of what it should be.. I am new to outboards, so any ideas what this could be?
Howdy, Rusty. I'm curious how you know power is only half. Did it make more power in the past?<br /><br />If you are really down 50%, you are probably running on one cylinder. <br /><br />By removing and grounding each plug wire, one at a time, you can determine if this is the case, and which one isn't making power. You can also determine if the problem is no spark.<br /><br />If there is spark but no power from one cylinder, you may have lost compression on that one or you may have lost a reed valve.<br /><br />Run a compression check. If the cylinder has good compression (over 90psi and within 10 psi of the other one) you probably have a reed valve problem.<br /><br />Let us know what you find.<br /><br />Red sky at night. . .<br />JB
