I've got a 1997 Yamaha 90AETO 3 cylinder 90 HP outboard. I've taken it out twice before with no problems (once for three days). I went fishing last night and struck major problems. <br /><br />I'd been running with no issues for about 20 minutes when I noticed a horrible burning smell. I looked first at the battery isolation switch, which was in the process of melting ! I immediately cut through the cables to the batteries.<br /><br />I disconnected the battery switch, and tried starting the engine again, this time hooked up directly to the battery. The trim and tilt works, but nothing happened when I turned the key. <br /><br />I opened the outboard cover to be greeted by a sickly burning smell. A rubber tube that was touching the starter motor had almost melted through. I pulled the boat through waist deep water for about 1/2 mile, the rowed the 23ft boat 2 miles back to the dock. Not a nice trip !<br /><br />Anyway, when the key is turned, the relay on the positive makes a clicking sound. There is 12v supply to the positive on the starter motor when the key is turned. I removed the starter motor, and tried connecting this directly to the battery... Nothing. I tried pull starting... to no avail. a couple of facts that may help pinpoint the problem<br /><br />1. The ignition switch on the control box occasionally sticks in the "on" position (I'm waiting for a new one to be shipped), meaning that it is possible that the starter motor was left running for the 20 minutes. <br /><br />2. After about 10 minutes of troubleshooting, I noticed that a rubber water tube has become disconnected. However, when a hose is connected to the rinse connection, water comes out of the telltale at a steady pace. <br /><br />3. I believe that the battery switch was in the "Both" position for the 20 minutes before it bagn melting. I have dual batteries connected in paralell. <br /><br />4. The starter motor definitely smells like the burning smell, however, after having been removed for a number of hours, the engine retained a very strong burning small.<br /><br />5. The flywheel turns without a great deal of resistance.<br /><br />6. The plastic isolation switch had begun to turn to liquid. I'd been at medium revs for the first 15 minutes, then just putting along looking for somewhere to anchor when I first noticed the smell. <br /><br />I appreciate any sggestions that you may have. The boat is about 50 miles away, so I will not get a chance to try them until next weekend. I've bought home the starter motor. Is there any way that I can check whether this is still working. <br /><br />Thank-you in advance<br /><br />Liam
