No spark on a merc 25, Help ?

[gaddy]

Last fall I was running up the river and got to the top of the troll lane, throttled down and it went dead. Got towed in. All of the checks I have made equals no spark to either cylinder. Can any one tell me how to test the stater and switch box ? I have been told it is very rare to loose both coils at the same time.
It's an 83 merc 25 pull start with a console, not a tiller. I ran power through the kill switch and all is good there.
No one wants to work on an older motor so I am left trying myself. I don't have a bunch of disposable cash at this point any way.
I have replaced connectors and wires to the coils (used copper instead of the stainless).
Would it be in my best interest to just replace the stater and switch box and be done? I haven't been successful finding part #s on line. Maybe back to the dealer with a s# and a check book?
Any help would be appreciated.

[Happy Gilmore]

does a two cylinder merc have two coils? also, have you simply pulled the plug and simply looked to see if there was no spark? My old merc occasionally ate spark plugs. They'd break inside and just short out. I think a merc plug is under $5.

[gaddy]

Two separate coils. Plugs were replaced. There is supposed to be a way to test the ohm's from the stater and to check out the switch box. I haven't been able to find any thing on-line showing the procedures or which points to test.

[Happy Gilmore]

You could try jump starting it directly at the starter. Mine was old and the control harness wires had all rotted out. One of the first issues was a short which didn't allow the starter to kick because the wire was sensing it in gear. Wouldn't allow it to turn over.

[gaddy]

It's a pull start with no battery connected to it. I hope I get this figured out soon.

[Happy Gilmore]

It's a pull start with no battery connected to it. I hope I get this figured out soon.

But you said you have controls right? The gear position sensor was the first issue I had. I rewired that a long time ago. Then everything else went to hell.

[gaddy]

The gear position sensor never crossed my mind. It was still in forward, I was just throttling down, rpm's slowed untill it was dead. I'm thinking switch box but it could be anything. I see another thread in Tri-Cities looking for help. Does any one know of a mechanic that does side work?? I can do the replacement of most everything but need help with the diagnoses before throwing a bunch of money at it.

[lokidog]

That's kind of where I sit with outboard repair, "tell me what the problem is and I can likely take care of it".  No fuel?  Clean out the carbs. No nothing, ugh....

Have you made sure your ground connections are all good?  I had a Johnson 15 that kept cutting out and then wouldn't spark, turned out a ground connection had gotten corrosion in it.

Of course, it is a Mercury.....       

[CP]

I once owned a similar vintage Mariner which is supposed to be very similar to the Merc.  It had 2 kill switches, a push button and a toggle.  The wiring to the push button switch shorted to ground under the twist grip throttle.  That kills the spark completely.  I’m not sure if your engine is the same but this is easily checked with an Ohm meter. 

Check between the kill switch wire and ground, if you don’t get and open circuit that is your problem.

[gaddy]

This unit has a toggle on the shifter and a second with the cord. I inspected all connectors to the swich then unhooked from the switch box, ran twelve volts through it and tested with a test light. Tried for spark with the switches disconnected and no spark.

[gaddy]

I may have to try and run down a service/repair manual. I asked at the first shop that that said they don't work on older models and the gal said the latest version they carry wont go back that far. Any one have one laying around that covers an 83 ?

[Dhoey07]

I'm have one that I am pretty sure covers an '83 25hp

[gaddy]

Would you happen to be in parts unknown around Tri-Cities ?

[Dhoey07]

Spokane Valley

[gaddy]

Is it something you would be willing to part with ?