Question for the 1994 Evinrude 40 hp experts

[knobby]

I have a 94 40 hp Ev that keeps me scratching my head. One day, it will fire up, runs great. Never any problems running, problem is tomorrow it might not fire a lick, no spark. Took it to the marine dealer, changed the kill switch after a series of tests, it fired up a couple times since, but today, no spark again. Any helpful input would be great. Plugs, packs and coils checked out ok.

 

[fishnfiend]

Re: Question for the 1994 Evinrude 40 hp experts

So starter always cranks, but spark to cylinders is intermittent? Probably not neutral safety switch, per se, but I'm wondering about exposed/broken wires in the control box or between control box (nss, kill switch, ignition switch) and engine. If it were mine, I'd check every wire for continuity - have a buddy wiggle the wires to simulate driving the boat while you test. Also, check for broken wires/poor ground connection at the powerpack. This is one of those fun intermittent electrical puzzles that has an answer. Please post any follow up so the rest of us can see the cause.

 

[knobby]

Re: Question for the 1994 Evinrude 40 hp experts

It always happens at first attempt to start, never after it's been started. One day, crank right up, next dead as a hammer, no spark.

 

[fishnfiend]

Re: Question for the 1994 Evinrude 40 hp experts

So maybe it is up in the powerhead somewhere, where heat causes expansion to broken or corroded wires - just enough to make contact?? Not advising you to throw parts at the problem, but could be powerpack internals or or ground or power supply - your test was just done at a time when things were making contact. If you have access to a known good powerpack, it would be interesting to see if a swap makes any difference. What about the wires from the pickup sensor on timing plate to powerpack? It's always bugged me a little to have solid copper wires attached to a moving mechanism - bound to cause a break sooner or later. Maybe yours is happening sooner...<br /><br />You'll get her figured out. Let us know when you do.

 

[knobby]

Re: Question for the 1994 Evinrude 40 hp experts

thanks, I'll get back on it in a day or so and let you know what happened.

 

[fishnfiend]

Re: Question for the 1994 Evinrude 40 hp experts

bump