Mercury 125 ignition, voltage problems

[CastleRock4me]

I have a 1996 merc 125 that has a couple problems. I had the boat out this weekend and it ran great at idle; however, would not rev over 3000 rpm under load (fine at idle). Also, the voltage meter was reading in excess of 16volts.

I did a quick look over of the motor and in looks like cylinder 3 and 4 are not firing.

Would a bad regulator cause the 3 and 4 cylinders not to fire? If not, what do I check o diagnose the problem?

Thanks

 

[CastleRock4me]

Re: Mercury 125 ignition, voltage problems

bump

 

[Chris1956]

Re: Mercury 125 ignition, voltage problems

You should get on the CDI.com or Dolphinmarineservices.com web site and look at the troubleshooting guide for your ADI ignition.

That motor will have a high speed and a low speed stator winding. If the motor will not rev up, the high speed winding may be bad. Of course that is just a starting place. Hopefully you have an ohmmeter, and you can test the stator windings with it.

 

[hkeiner]

Re: Mercury 125 ignition, voltage problems

http://dolphinmarineservice.homestead.com/ign5.html

 

[CastleRock4me]

Re: Mercury 125 ignition, voltage problems

The tests indicate a bad switch-box. I ordered one and will post back with results. Still wondering why the 16v problem. Could the swithbox cause this?

 

[j_martin]

Re: Mercury 125 ignition, voltage problems

The charging system and the ignition system are unrelated except the coils happen to be wound on the same general piece of iron.

16 volts isn't unusual. You might have an old battery that needs replacement. At any rate, the battery charging circuit is isolated from the ignition system. They do not interact in any way.

hope it helps
John

 

[CastleRock4me]

Re: Mercury 125 ignition, voltage problems

Got the bottom two firing; however, now there is a high speed miss. I disconnected the brown wire from the switch box to the RPM limiter and it ran fine this way. Does this indicate a bad RPM Limiter? Should I check somthing else.

Is it unsafe to run it this way?

Thanks