merc 115 2+2 no spark?

[emzle]

Well, now that I got a timing light, I have no spark on cyl 1 or 2. 3 and 4 are ok. So now am I looking at the trigger coil? The manual says to install test harness, which I don't have, but wondering if other ways to test the trigger. Have done resistance test on stator, and it tested ok. Would the rectifier cause this?Sincerely need help.<br />Mark

 

[emckelvy]

Re: merc 115 2+2 no spark?

The trigger can be resistance-checked with a meter. Also, if you hook up to one or the other of the 2 pairs of trigger wires, with the meter on ohms turn the flywheel a bit with your hand and you'll see a change in the meter reading as the trigger generates a small amount of current. This is normal and shows the trigger is working as it should.<br /><br />If the stator and trigger ohm-out OK, likely your switchbox is bad.<br /><br />Here's a good place for research and diagrams etc:<br /><br /> http://biggerhammer.net/mercury/factory_manuals/Service_Manual_Index.html <br /><br /><br />HTH.........ed

 

[emzle]

Re: merc 115 2+2 no spark?

Thanks Ed. Have the manual in hand too and will try your trigger test. I started out with what I thought was a fuel pump problem, then now have graduated to an electrical ignition issue. Not sure that a bad CDM hasn't been my problem all along!! At first it was running terribly for 5-10 seconds, then dying. I did swap #3 CDM and #1 CDM while troubleshooting, and now have no spark on 1 and 2. Will swap back to see if spurty idle returns? Am learning quite a bit on troubleshooting this finicky motor.

 

[emzle]

Re: merc 115 2+2 no spark?

Thanks to Laddies (Bob) and his helpful link to the Rapair Troubleshooting Manual(rapair.com), which outlined a great way to isolate my problem. I narrowed it down to the #4 CDM, replaced it and now have running motor. Also thanks to Ed Mc. and everyone else who has helped me work my way thru this. I have told all my boating friends about you guys. <br />mark