1970 Evinrude 115 Spark problem

[scroff]

I know I am probably beating a dead horse with this discussion, but I can't seem to find quite what I need in old posts. I recently purchased a boat with a 1970 Evinrude 115 (115083D) on it. The motor itself has very intermittent spark, specifically will start and fire a couple times then lose all spark. It will ahve no spark at all for a few minutes then regain it for the same thing. It has never stayed running for more than a minute or two before losing all spark. I believe I have a pretty decent understanding of this ignition system, and have tested the voltage into the pulse pack at cranking (the ignition safety switch has been removed but the charging system is working properly anyway), tested the stator, sensor, coil. I have cleaned all grounds and connections and double checked wiring for cracks or wear. My question is, before buying a $300 pulse pack, is it possible for a bad one to have intermittent spark like this? Also, if this is the problem, is there any cheaper route to replacng it?

Thanks

 

[boobie]

Re: 1970 Evinrude 115 Spark problem

If I had to guess, I'd say a bad pulse pack. If it is the original pack, better guess yet.

 

[scroff]

Re: 1970 Evinrude 115 Spark problem

Also, at some point the shift diode on the terminal rail has been removed from my motor. What would the reason for removing it have been? The lower unit shifts fine, so what purpose does that diode have?

Thanks

 

[charger_1]

Re: 1970 Evinrude 115 Spark problem

My understanding of that shift diode is to prevent shift solenoid coil burn-out