86---25hp Evinrude looses spark after 15min

[N2Crappie]

I have an 86---25hp evinrude that looses its spark to both plugs after it runs about 15 to 20 min. I have replaced the power pack---No help. I have checked continuity to the sensing coil(50 ohms) and the charging coil (600ohms)and checked both for shorts to ground. The kill switch is ok and the ignition switch grounds when off and is open when when on. I removed the coils and can not see any cracks or burn marks. I have wiggled wires until I'm blue in the face looking for shorts or open wires that are intermittant-no luck. I guess my next step is to replace the coils unless someone can give me a better sugestion. By the way the engine can set a couple of hours and then will spark again.<br /><br />Model E25TECDC<br /><br />Ser. No E0623542<br /><br />Thanks in advance for any help. I need to go fishing bad.<br /><br />N2Crappie

 

[Bass Runner]

Re: 86---25hp Evinrude looses spark after 15min

welcome to the forum, you say it has no cracks in the power pack, did you replace with a new one or another old one? if it was a old one it may be bad too.

 

[Reel Appeal]

Re: 86---25hp Evinrude looses spark after 15min

If those are the original ignition coils I would replace them.They may be "breaking down" from the heat after 15 mins. or so.Did you test the ignition coils when they warm after running?

 

[ob]

Re: 86---25hp Evinrude looses spark after 15min

Check the charge coil and pack output voltage when the engine won't fire before it cools down and see what you get.Charge coil output should be around 150v and pack output should be around 125v.Not likely both ignition coils would fail together.You can also use a mirror and flashlight and perform a visual under flywheel of the stator windings and see if there is any gooey meltdown in the making.The substance that the windings are sealed with can break down after a while and cause intermittent spark loss.

 

[N2Crappie]

Re: 86---25hp Evinrude looses spark after 15min

Thanks everyone for the prompt replies<br /><br />Bass Runner: I used a new power pack.<br /><br />Real Appeal: I will check the ignition coils when hot although it seems unlikely that both would fail at the same time.<br /><br />ob: I should have been more specific, the coils I removed were the charge coil and sensing coil. <br />Can I check these output voltages with a typical VOM and should I use DC or AC settings?<br /><br />Thank to you all

 

[ob]

Re: 86---25hp Evinrude looses spark after 15min

You can use a multimeter but it is advised to use a peak reading meter or a fluke with a DVA adapter.Set the multimeter in the A/C scale and multiply by 1.414 to get a voltage reading from the charge coil and pack.

 

[N2Crappie]

Re: 86---25hp Evinrude looses spark after 15min

ob Thanks I will try it tonight and let you know what happens.

 

[N2Crappie]

Re: 86---25hp Evinrude looses spark after 15min

I think I may have found the problem. I let the motor run until it quit again then started checking resistances again and found that the wire to the ignition switch is grounding in the off posistion as it should, but in the on position it is sending twelve volts back to the power pack from the switch. I cut the wire in two and started the motor and it ran great and smoother than it had been. I grounded the wire to shut off the motor. So I have to see if I have an internal problem in the switch, loose wires shorting to the kill wire, or just wired wrong. Any guesses which?<br /><br />Thanks