1971 50HP Johnson, turns over but no spark?

[powersledder]

Just picked up an old starcraft with a 50HP Johnson. The motor turns over just fine but it doesn't seem like it is getting any spark. Could not see spark and would not start after injecting gas into the cylinders. The PO just put new brushes in the starter, but the starter works so I don't think that's the problem? I also found a purple wire that was unhooked and it looks like a screw fell out that was holding it in? Also, I am 99% positive there is no kill switch/tether on this boat.



Anyone here have experience with this?

 

[jbjennings]

Re: 1971 50HP Johnson, turns over but no spark?

I believe that's a battery cd ignition. View attachment 93123
I believe it's similar to the 65hp wiring diagram I've attached. If I recall, the purple wire is for the electric choke and shouldn't be your problem. You'll have to troubleshoot the darned thing to see what's not getting or putting out voltage. There's a stator under the flywheel that I hear can go bad. The switchbox can go bad, too. Doubtful that both coils would go out at once, but possible. You'll need a manual to go through the ignition troubleshooting procedures with you.
Wish I had one.......
BTW, the ignition switch could also be bad, and should be checked as well. I wish I could be more helpful but ignitions aren't my best area..:redface: And I like your starcraft! Nice looking boat.

Oh, and the key IS the kill switch! Remember to use type "C" lower unit oil on that hydroelectric shift or "OMC premium" gear oil.
Good luck,
JBJ

 

[powersledder]

Re: 1971 50HP Johnson, turns over but no spark?

Thanks for the tips JBJ. The main problem here is I don't have much experience with these types of outboards. My Dad's Merc 115 we've never had to work on and my old Chrysler 6 didn't have an electrical mess like this motor does. But from what I've read I should try working my way from the coils to the powerpack to see if something is burnt out, but how?

 

[powersledder]

Re: 1971 50HP Johnson, turns over but no spark?

Anyone got some tips about how to trace a spark problem? I wanna get this thing on the water.