'77 115 Merc

[Big blue one]

This motor has performed well for me this summer. I bought it this winter. Last sunday I took it out. It started right up as usual. Ideled out from the dock just fine. I opened it up, got it on plane running about 3/4 throttle for about 2 minutes then it just stopped. Just like I'd shut off the key. I could hear a whirring noise coming from the motor but nothing else. I shut off the key and the noise stopped. Started right back up but ran rough. I shut it off and tried again. Started and ran just fine. It cut off on me one more time that day but re-started and ran great the rest of the day. It doesn't seem fuel related because there was no sputtering or winding down before it died; it just suddenly went 100% dead. Any ideas where I should start looking? Thank you very much for your help.

 

[Laddies]

Re: '77 115 Merc

The whiring sound sounds like a starter running and turning the key of and having it quit makes me think the problem could be a bad ign. switch as it would also effect the spark and that could be what shut the engine down also

 

[Tadd_P]

Re: '77 115 Merc

may be the ignition switch may not. Definately a wiring issue. Run through all the wires on the motor and wires running from the control box. Sounds just like a dead short to me. I have a 1979 inline 115 and she is picky as ever. Take the main wiring harness off from the side of the motor and make sure it is making good contact and put some grease on it before you reconnect the wire. Good luck man you have a real good motor there just as long as ya take care of her. Plan on a lot of maintence!