25 hp Mercury Outboard "no spark"?

Question

I have a 96 model 25 hp Mercury 2 stroke. It stoped running 2 weeks ago on the river. I have tested the spark plugs/ coils and are not getting any fire. We have replaced coils with new ones and it was sugested that the ignition box/ switch box was bad.. 250.00 later and a new box. We are still haveing the same result. No spark.... I have checked the safety switchs and they are both working, open in normal condition and when they are activated they read a short on the DMM. I'm not sure what any of the other wires on the Switch Box should read. Any suggestions or any place I may beable to find troubleshooting tips. I do not have a manual and would love to have this thing back in the water before one would get here if I ordered it right now.... Thanks for any help.

Answer 1

stator

Answer 2

Wayne,do you have electric start?

  You can contact me if you wish through this site and I will try to help if possible.

35 years as a marine tec.

Answer 3

This is the reason outboard owners shoud not attempt to repair their own motors.  Any experienced, certified marine mechanic will tell you that when there is an ignition problem, the last component you should suspect are the coils.  They RARELY go bad.  The proper procedure is to work from the top down, starting with stator output.  From there you check the output from the switch box which goes to the coils.

If the stator is putting out the proper voltage, then it is good.  If not it is bad and needs replaced.  But if a stator goes bad it can knock out a switch box too.  So once the stator is replaced output from the switch box needs checked.

If the stator is good then you need to check the output from the switch box.  If the voltage output is correct, then the switch box is good.  But 99% of the time when there is an ignition problem and the stator is good, you will find that the switch box is not putting out the proper voltage spec.

If the switch box tests good, that only leaves one component, the coils.  If everything to the coils tests within specs then the coils need replaced.

But like I said, it is very rare for a coil to go bad, let alone more than one at a time.

Take it to a dealer.