1971 Evinrude OB Engagement Fails

[Malwareman]

Greetings All,<br />After much research I have a few ideas on what might by my problem but I still need some help on diagnosis as well as the best path to take regarding the repair of my 1971 OB 100 HP Evinrude motor.<br /><br />I've had the boat/motor for 2 months - worked fine until this last weekend. At first it wouldn't engage in reverse. It starts up fine, throttle up fine, but doesn't go anywhere in reverse. I didn't really notice this until later in the day, when both forward and reverse went out. I got towed to shore and was able to then start it up fine, throttle fine (like before). While it still wouldn't go in reverse I could get it to engage in forward. It's an electric shifter, so I'm thinking a solenoid is at fault...which is hard to replace as I understand it?<br /><br />Other ideas include a possible hydraulic pressure problem from water in the lower unit or the wrong type of oil in the lower unit? Perhaps a flush and replacement with new oil in the lower unit would fix it? Another idea from reading is that their is a wire with a short in the lower unit that may be causes it too? Either way, replacing the oil the lower unit looks like a good first step?<br /><br />Recommendations for good books, repair parts, and troubleshooting this particular problems is most appreciated. Please cc me at dunhamk@rmci.net with your post <br /><br />Thank You!