2005 Mercury 115 EFI 4 cycle. no fire.

[RandyJ]

Lanyard hooked up, cranks over just fine, has pulsing voltage to coils. No fire. When I use an ohm meter to check for resistance or continuity from sparkplug wire to ground or any terminal on the coil wire I get nothing. I do get continuity between terminals where wiring harness connects to coil. I don't want to buy new coils unless I can confirm that BOTH are bad. This boat had been sitting up for a couple of years. Got it cranked and it coughed and sputtered quite a bit but we did run it all evening couple of weeks ago. Next morning couldn't get it to hit a lick but got a pop backfire now and then. Fuel is fine, injectors clean and work great. Just NO FIRE using spark checker from CDI. Big question is for sure how to check coils to confirm whether good or bad.??? I have a DVA and an analog volt meter.

 

[alldodge]

If your kill switch is not tripped, I would start in the link below on how to test for spark
http://boatinfo.no/lib/mercury/manuals/115.html#/92

 

[RandyJ]

I'm still to these 4 cycle engines. Everything seems to check out on the engine so I'm going to have to pay closer attention to the kill switch and ignition switch. I don't know if the kill function is done by completing a ground circuit as is normal on most outboards or if it breaks a circuit shutting off electricity to the engine. I do know that with switch on there is 12 volts to the coils.... but it's not getting spark to the plugs when using a very high quality spark checker.

 

[RandyJ]

This boat has gremlins... I took the battery out to charge it then when I put it back in the key switch will not turn it over as if it is in gear. I did continuity checks on the key switch, neutral safety, and kill switch. They are working correctly. This guy has had problems before when he was out on the lake, stopped the boat then it wouldn't do anything when key was turned.... that's what's happening now. Looks like we have a bad electrical connection somewhere and I'll just have to chase it down with an ohm meter.

 

[RandyJ]

I DID find a broken wire in one of the connectors of the wiring harness... It will now crank over but still will not start.

 

[alldodge]

Hope one of the outboard guys come in, maybe tomorrow, it being the holiday weekend.

 

[RandyJ]

Yep. These newer engines with advanced electronics are still new to me. I've worked on a couple of 4 cycle outboards and still got a lot to learn. Engine basics are not a big deal but I still run across one now and then that makes me pull my hair out. Finding gremlins is the most frustrating....

 

[RandyJ]

Don't know how it did it but apparently something happened to the sparkplugs and I'm assuming it was caused by a short in the wiring harness since that seems to be the only real problem it had. Once I put in new sparkplugs after fixing the wiring harness connectors she cranked up and ran better than new.... kinda weirds me out. Ohm meter showed spark plugs to be good and they looked good.