Will a 77 115 run with a dead battery???

[emilime75]

I have a 77 115 horse motor with thunderbolt ignition. Will this motor run on it's own if hand cranked to start? I know running this motor with no battery hooked up will fry the rectifier, but what would happen if the battery is hooked up but dead? Will the stator supply enough voltage/current to run the ignition?

 

[emckelvy]

Re: Will a 77 115 run with a dead battery???

Distributor-fired CDI ign requires 12V to run. I'm assuming your motor has a belt-driven distributor. No way can the stator make enough voltage at rope-pulling speeds to energize the ign.

Later-model ADI (distributorless) systems are self-energizing and could theoretically be roped-over to start.

HTH..........ed

 

[emilime75]

Re: Will a 77 115 run with a dead battery???

That's what I was thinking, but someone old school was telling me it should run regardless. I assume they may be used to older/smaller outboards that did not have electronic ignitions.

The reason I ask this question is because a couple of weeks ago we were out on the water and everything seemed ok all day...when we started back for the shore/boat ramp the motor died and would not start or crank even. When we got home I checked the battery and it was down on voltage. Haven't had time to troubleshoot yet, but I am guessing the rectifier went out and was not charging the battery all day. It's not a very good battery to begin with. We luckily had a couple of paddles on board and were able to row the last mile back to shore. My wife was a good sport about it as this is our first ever boat and has been a learning process...for sure.

 

[Bifflefan]

Re: Will a 77 115 run with a dead battery???

This is a fine example for a second battery. Altho by your on admittance your primary batt is not in top shape. That would be the first thing to replace. Then i would get a second one and a perko switch, so you can have a spare at the turn of a switch. Its cheap insurance when you factor in some of the things that can happen. Even if you only get the second batt and just carry the nessarry tools to switch the cables, its better than nothing.

 

[Chris1956]

Re: Will a 77 115 run with a dead battery???

The only time you will need a second battery is if you have lots of electronics that you plan to run, while on the water.

if the motor's charging system is working, and the battery is good, and you have minimum electronics power demand, you will be fine. Today's GPS and FF take minimal power, as do the gauges.