40HP Mariner(1988) cranks, won't start

So a buddy and I went fishing yesterday. Got the boat in the water, motor started right up. Went about 2 miles out to a potential fishing spot and killed the motor. Fished for awhile(no luck) and decided to move, turned the key and the engine cranked but would not start. I always make sure to check the water stream before heading out, and periodically while moving. It was always solid, so I don't think it overheated(it has done that before and not started when the impeller failed and I didn't notice) Checked gas, fuel pump, etc. All was good. So after a VERY long trip back with the trolling motor, the day ended. I got home and pulled the plugs, they were wet, so it was definitely getting gas(probably flooded after the repeated start attempts). New plugs, grounded them to the block and cranked it, no spark at all on either plug wire.

Im not sure what would have failed so abruptly to cause this? Coil? Seems like there would have been some signs of failing ignition components, but I don't know. Any ideas where to look? What to test first and how?


Thanks all!

Take the silly stuff away first: did you pull the dead-man switch by mistake? that will immediately cause no spark in either cylinder. Otherwise, here are a couple of troubleshooting guides to use as starting points:

https://www.outboardignition.com/tips.asp
https://www.cdielectronics.com/support/

Good luck!

I did check the kill switch. Even flipped it on/off several times with the same result, so unless it is actually a bad switch... Ill check out the links. Thanks!

I never posted a resolution to this, I know its years old, but may help somebody. Coil was replaced, same issue. Ended up being the CDI unit in the motor, when it heated up it would fail causing no ignition, and finally it failed completely. Just FYI for anyone having a similar issue with a Mariner.

traybore said:

Just FYI for anyone having a similar issue with a Mariner.

Click to expand...

Mariner and Force coils are NOTORIOUS for intermittant failures ... one hour (or day) they woukd work ... and the next hour (or day) they would NOT work ...

Did you buy the parts from Yamaha?