1993 mercury 60 hp 2 cycle no spark bottom cylinder

[swettbrook]

My 1993 Mercury 60 HP 2 cycle 3 cylinder outboard has no spark on bottom cylinder. The spark plug wire and coil are good as they get spark if place in middle position. The max rpm is 3000 - 3400. The motor starts and run OK.
Where do I look next to solve my problem. Every thing on the fuel side is eliminated as I do not get fire in the bottom cylinder.

 

[Texasmark]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

Does your engine have 3 CDI modules (coil in your post???) like it's big brother the 3 cyl 90 hp? Trouble shooting is easy with them. Just unplug another module and put in slot #3. If the problem follows the CDI, you have your smoking gun. I think you can buy them on here for about $100. Beware of buying used ones, or ones from a questionable source. They may be defective and things of this nature are usually not returnable. So in thinking you're getting a really great deal you may wind up just getting SCREWED!.

HTH,
Mark

 

[swettbrook]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

Does your engine have 3 CDI modules (coil in your post???) like it's big brother the 3 cyl 90 hp? Trouble shooting is easy with them. Just unplug another module and put in slot #3. If the problem follows the CDI, you have your smoking gun. I think you can buy them on here for about $100. Beware of buying used ones, or ones from a questionable source. They may be defective and things of this nature are usually not returnable. So in thinking you're getting a really great deal you may wind up just getting SCREWED!.

HTH,
Mark

I have three coils. The bottom cylinder did not have any spark going to the plug. I have all new spark plugs and I have replaced the bottom coil. I still did not get spark. I changed the bottom coil to the middle position and got spark. The problem is not the coil or the spark plug wire. I still do not know what the problem is.

 

[GreenHornet763]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

I changed the bottom coil to the middle position and got spark. The problem is not the coil or the spark plug wire. I still do not know what the problem is.

I think you solved it hear, sounds like a bad coil #3

 

[Texasmark]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

Reading what I think you said. You removed CDI#3 from it's location and put in slot #2 and it worked. You didn't say that #2 in slot #3 didn't work either directing us to an input wiring problem to #3. I am assuming that #2 wouldn't work in slot #3.

Looking at the CDI #3 slot input wiring:

Black: ground
Black/yellow stripe: Trigger kill....from the ignition switch and all 3 CDI's are fed in parallel from one wire from the control box. Really doubt this has anything to do with your problem.

White: Trigger from trigger coils under the flywheel. Fires the CDI producing the high voltage.
Green/white stripe: Voltage source to fill up the storage capacitor in the CDI that delivers the energy to the coil to produce the high voltage and fire the plug. Without this input there is no energy to send to the plug to fire it when the trigger says go!

Slot #1 has a separate wire from the stator (under the flywheel).

Slots 2 and 3 are paralleled off another separate wire from the stator. If #2 CDI position is working and #3 isn't, there is an opening (open circuit, corroded connection not making contact, pinched wire that cut through the conductor and opened it) in the green/white stripe wire from #3 to where it joins the green/white stripe wire from #2.

I would assume that you don't have to go up under the flywheel to find it. I'd assume the union is very near both CDI's. Cut the tie wraps and trace that wire from both CDI's till you get to the junction. Inspect it for corrosion and also inspect it's connection on the #3 CDI connector.

From the symptom given I think you will find your smoking gun. Really, there isn't anything else it could be. I'm sitting here looking at the maint manual wiring harness and that's all there is.

HTH,
Mark

 

[swettbrook]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

Reading what I think you said. You removed CDI#3 from it's location and put in slot #2 and it worked. You didn't say that #2 in slot #3 didn't work either directing us to an input wiring problem to #3. I am assuming that #2 wouldn't work in slot #3.

Looking at the CDI #3 slot input wiring:

Black: ground
Black/yellow stripe: Trigger kill....from the ignition switch and all 3 CDI's are fed in parallel from one wire from the control box. Really doubt this has anything to do with your problem.

White: Trigger from trigger coils under the flywheel. Fires the CDI producing the high voltage.
Green/white stripe: Voltage source to fill up the storage capacitor in the CDI that delivers the energy to the coil to produce the high voltage and fire the plug. Without this input there is no energy to send to the plug to fire it when the trigger says go!

Slot #1 has a separate wire from the stator (under the flywheel).

Slots 2 and 3 are paralleled off another separate wire from the stator. If #2 CDI position is working and #3 isn't, there is an opening (open circuit, corroded connection not making contact, pinched wire that cut through the conductor and opened it) in the green/white stripe wire from #3 to where it joins the green/white stripe wire from #2.

I would assume that you don't have to go up under the flywheel to find it. I'd assume the union is very near both CDI's. Cut the tie wraps and trace that wire from both CDI's till you get to the junction. Inspect it for corrosion and also inspect it's connection on the #3 CDI connector.

From the symptom given I think you will find your smoking gun. Really, there isn't anything else it could be. I'm sitting here looking at the maint manual wiring harness and that's all there is.

HTH,
Mark

The green wire going to the bottom cylinder does not have power. I attached green wire to #2 CDI and no spark. Wire go into sealed switch box and out to trigger below fly wheel. The information given has been helpful in trying to fix problem. I need to get time and puller to remove fly wheel to take the next step. Will let you know when I get there.

 

[swettbrook]

Re: 1993 mercury 60 hp 2 cycle no spark bottom cylinder

The green wire going to the bottom cylinder does not have power. I attached green wire to #2 CDI and no spark. Wire go into sealed switch box and out to trigger below fly wheel. The information given has been helpful in trying to fix problem. I need to get time and puller to remove fly wheel to take the next step. Will let you know when I get there.

The problem was a faulty switch box.

 

[foleyba4]

Do you still have this motor?