50 hp Johnson no spark

[cutlass442_1966]

Hello all,
A friend recently loaned me his pontoon boat with a 50 Johnson outboard on it. Like most things I borrow, it immediately quit working. It died after a couple hundred yards of idling, then cranked over for a minute or two sounding like it had not spark, but then finally fired up. I turned back towards the dock and it died again. After being towed back, I put a spark tester on a plug and cranked the motor over and had no spark. I started checking all the grounds I could find, unplugged various connectors and cleaned them up. A couple of times while turning it over it would catch and fire for a few revolutions then die again and not make any more spark. I am a 60s car guy and know nothing about outboard motors, this is the first one I’ve ever looked at under the hood. Can anyone give me a starting point on troubleshooting? Or maybe point me towards some good wiring diagrams? Any info would help. Thanks!

[jamwil]

This might not be much help. I also work on cars have my life
I just started working on boat motors a couple years ago. But 1 thing I did notice, and I know a lot are going to say I am wrong, but thank of the boat motor as a car motor just laying the wrong way. think of if it was a car motor what would you do. There is a power pack on the side that has a wire coming from it going to coil then to the spark plug.

[boats.net]

Check your safety lanyard switch. A bad connection or deffective switch could cause loss of spark.