Newbie with Mercury 115 problems...Ignition switch and no spark

[Flossyb20]

Hey guys
So I've been doing nothing the last 2 days but checking out threads on your site here, trying to get my 88 Mercury 115 running. This is my first boat ever, so this is all new to me. I know how work on cars like crazy, but I'm not familiar with the ins-and-outs of the inline 6 2-stroke. So here goes: Got the boat yesterday, without hearing it run (don't worry, I didn't pay much for it-200.00 w/trailer) comp. test checks out great. It needed a new ignition switch before I could fire it - so, where does the purple wire hook up to on the back of the ignition switch? It's the one that runs through the little speaker on the controls. I ran the red wire to battery, and hooked up the starter and ignition wires properly (power to both when appropriate). The switch I got claims to be the proper replacement for my motor, but also has terminal for a magneto...what goes on these? I understand that this has a stator, not a magneto, plus, there were no grey wires going into the back of the oem switch, whcih the wiring diagram says is to the stator. Moving on...the power is getting to the switchboard, but NONEof the cylinders are firing...any thoughts? I was hoping I just switched some wires on the new switch, but everything coming out of the switch does what it's suppose to. Thanks for any help.

 

[Cogburn]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

You should look at the manual to figure out the wiring.

http://docs.google.com/fileview?id=...hkYTUtZTBkNDNmOTNiY2Iz&authkey=CPmdsO8K&hl=en

The switchboxes do not get any 12v power from the switch.

The black/yellow wire on the switchboxes is the ignition kill-it is grounded out by the ignition switch to kill the spark and therefore shut off the motor. The black with yellow wire also goes to a mercury switch to kill the ignition if the engine is tilted up.

Unhook the black/yellow wire and there should be spark.

 

[199675hpforce]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

Simple landyard switch to on position? Make sure on outboards that your getting right mix of oil to fuel. If you adj carbs rich is better than lean. Your 88 should have oil injection make sure your getting nice blue color when starting.

 

[Flossyb20]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

Thanks for the tips...went out today and got the "real" correct switch. Haven't put it on yet, but we'll see tommorow. I didn't realize that the black.yellow was ground/kill switch, that would explain a few things. Also, the oil injection has been removed, so no issues with that now. We'll see how things go tommorow. Thanks again.

 

[Flossyb20]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

Ok guys, I got the new switch on, cleaned out the carbs, and it fired right up, but without the rectifier hooked up. What does that mean? Also, it ran for about a minute, idled down, and cut off. I cranked it back up, took a while to fire again, but when I got it running I tried to open up the throttle, but it just bogged down, like the timing wasn't advancing. Any ideas? I was thinking maybe the trigger is bad, which would explain both problems...??

 

[Cogburn]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

My guess is the rectifier is shorted and/or stator problem for the no spark with the rectifier hooked up.

The bogging sounds like lack of fuel. Turn out the idle mixture a couple turns and see if it helps. Or try tapping the choke while attempting to throttle up. The carbs may be plugged up.

 

[arsenalpsu]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

you need to do a lync and sync to check timing and make sure carbs are set correctly. Search on here for the L&S from Clams which will get you close, only thing wrong with it is the primary pickup timing, which is 4-7 ATDC, not before like stated there.(b/c your motor is CDI ignition not a distributor type) Once you do this if you still have issues could be switch boxes, trigger or stator- go to here http://www.cdielectronics.com/downloads/troubleshooting guide/
and find your engine and learn how to test each part. You will need a DVA tester.

The rectifier in that motor only charges the battery and has nothing to do with spark. All energy for spark comes from the stator right to the boxes/coils. Also remove the idle stabilizer, it's the small black box on the front cow support- about the size of a deck of cards. It advances the spark at idle but can also do so at WOT causing distruction.....and the oil injection being removed is a great thing.

 

[Flossyb20]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

Thanks again for all the tips. Went and bought a spark gap tester and compression gauge. Bad news is that #2,4,&6 cylinders have no spark...good news is that all cylinders are between 121-123psi, so it's worth fixing. Swapped the stator wires to the other switch like the CDI site said, and the problem stayed on the same bank, so I ordered a new switchbox, should be here early next week. Hopefully everything else checks out, and I can get to the L&S early next week. One quick question though, the wires to both the stator and the trigger are pretty oil soaked, and starting to deteriorate, can I just splice new wires in, or are they resistance wires?

 

[Dave1027]

Re: Newbie with Mercury 115 problems...Ignition switch and no spark

You can splice new wires. They are not resistance wire. I would solder two ends together inline and shrinkwrap the connection tightly. Best to stay with the color code and use stranded copper wire at least as fat.