1975 Evinrude 75HP (Mod# 75743S)
New to me old boat. Had the boat out four times and the first three trips I noticed that pulling out of the harbor in the morning when I went WOT, she would not plane. After the engine warmed a bit, the missing cylinder would kick in and she would run perfect for the rest of the day. This morning was a different story. I took her out and it did the same thing; however, it took a full 30 minutes of slow cruising, off, on before something kicked in and away she went running perfect. Pulled into a cove in a no wake zone, slowed her down and a couple of minutes at slow speed, I could feel a cylinder go dead again. Loaded her up and took her home. Pulled the plugs to check for fouling (None). Put an induction light on all plug wires and noticed bottom, middle good but zero spark on the top cylinder. Thinking perhaps the coil....
I'm no outboard mechanic, but I'm thinking if I switch out the top cylinder coil with the second, if the problem follows to the second and I have spark on the top then it's likely the coil.......correct?
Also pulled the harness covers and checked all the wiring and contacts. All were clean and tight with the exception of the (what I believe used to be red wire) off of the rectifier. Most of the insulation has cracked and fallen away from this wire. I've patched the wire and heat shrunk two layers over it. Put it back together and still no spark on the top.
I'll be ordering a new rectifier on Monday. Seems if that wire was complete toast, the engine would not run at all instead of the intermittent issue.
Any thoughts or recommendations???
Respectfully......Mark
New to me old boat. Had the boat out four times and the first three trips I noticed that pulling out of the harbor in the morning when I went WOT, she would not plane. After the engine warmed a bit, the missing cylinder would kick in and she would run perfect for the rest of the day. This morning was a different story. I took her out and it did the same thing; however, it took a full 30 minutes of slow cruising, off, on before something kicked in and away she went running perfect. Pulled into a cove in a no wake zone, slowed her down and a couple of minutes at slow speed, I could feel a cylinder go dead again. Loaded her up and took her home. Pulled the plugs to check for fouling (None). Put an induction light on all plug wires and noticed bottom, middle good but zero spark on the top cylinder. Thinking perhaps the coil....
I'm no outboard mechanic, but I'm thinking if I switch out the top cylinder coil with the second, if the problem follows to the second and I have spark on the top then it's likely the coil.......correct?
Also pulled the harness covers and checked all the wiring and contacts. All were clean and tight with the exception of the (what I believe used to be red wire) off of the rectifier. Most of the insulation has cracked and fallen away from this wire. I've patched the wire and heat shrunk two layers over it. Put it back together and still no spark on the top.
I'll be ordering a new rectifier on Monday. Seems if that wire was complete toast, the engine would not run at all instead of the intermittent issue.
Any thoughts or recommendations???
Respectfully......Mark