Originally Posted by Hookmeup
thanks for the schematic My issue is port engine start button circuit stopped working but I can start by jumping the start solenoid. I checked the helm button and I was ok. Then I started reading the wiring in the engine room where bridge bundle connected to the engine harness. Under load when the start button was pushed voltage to the starter solenoid was too low to.engage solenoid i also the med what I thought was wire from harness connection in the engine harness to start solenoid and found no continuity. There's also a Marinetics start box on the bulkhead that I have not investigated and have no docs on. The schematic you posted shows a solenoid #10 that appears to send the 12V to the starter motor solenoid. I saw the red and white wires on the starter solenoid so the colors appear to match the schematic you sent. so maybe it's just a bad #10 solenoid? in fact I think I saw a spare on the boat....DO these go often? I have a stop button in my system which does not appear in this schematic all my key switch does is power up the engine wiring and start the buzzers until Oil press stops the buzzer. But my engines will run if you turn the key off...until you push the stop button.
Try removing the dashed wire from #10 and use a jumper wire to apply 12V directly to the post on #10 from the start battery. The engine should crank, but not start. Assuming the engine cranks, this will rule out #10 as the culprit. If the engine does not crank, the ground connection to #10 may be bad, or #10 is bad.
If you find that #10 is good with the test above, you need to trace the wiring from #10 to the start button and figure out where the excessive resistance is. All of this wiing is part of the boat, not the engine, so it''s impossible for me to say precisely where the problem is. While you are working on this stuff, it would be a great time to install a momentary SPST NC switch in the fuel solenoid wiring and a momentary SPST NO switch on #10 post from the test above and the battery +, in the engine room. You can use these to start and stop the engine as long as the key is on. They may be handy for troubleshooting later and can serve as backups in case something happens to the helm wiring.
Once the engine is running, killing +12V power or ground to the fuel solenoid should kill the engine, but you may have a latching relay in the circuit that has to be manually shut off with the separate stop button. That relay would come between the ignition switch and the fuel solenoid and would not be shown in the diagram I posted.