blew ignition coil & fried wiring on 1967 evinrude 33hp - runs poorly after repair

[rgnjc]

blew ignition coil & fried wiring on 1967 evinrude 33hp - runs poorly after repair

I could really use some help troubleshooting this repair job. Last week I was on the lake adjusting my carbs, and the motor ran great. Foolishly I messed with the electrical and hooked up lights incorrectly to the ignition switch. When I started the motor I fried an ignition coil and some wires in the harness that runs from the junction box under the transom to the motor (see pics). The engine ran poorly (it was only firing 1 cylinder) but I was able to drive it back to the dock. I feel like an idiot, but it’s my first boat so I'll chalk this up to experience. I have since disconnected all the accessories (which the previous owner had hooked up to the ignition switch) and the lights.

To repair this, I first cleaned the entire magneto since it was all crapped up with burnt coil plastic and gunk (looks brand new inside it now). I replaced both ignition coils (kept the non-melted one as a spare) and both condensers. I did not replace the points since they didn’t look to be affected although I checked their gap. The spark plug wires looked OK. The wiring harness that connects from the junction box to the motor was the original wire bundle, so the wires were cracking and brittle to begin with. I made a nice new harness with 14 gauge wires (correct thickness) and hooked it all up between the junction box and the motor. Also, I replaced the spark plugs for the hell of it (same plug, 0.03 gap).

After all these repairs, I took the boat on the water late in the day today (so I only ran it for like 10-15 minutes) and it ran, not great, but it didn't sound like it was running optimally. It was running on both cylinders, but at low rpms it was idling poorly and even stalled out a few times. It also had some trouble starting (starter works normally). At full throttle it sounded like it reached high rpms, but again it didn't sound like it was running as well as it did before I blew the electrical system out and now it has a deeper bass-like sound to it. The wire bundle running from the ignition switch to the junction box looked OK although I can’t inspect the vast majority of it. There is a solenoid switch in the junction box, I’m not sure how to test if that is OK, is it possible I fried that as well and should I replace it? I ran out of daylight so I didn’t have much time to mess with it. Do I need to readjust my carbs to see if I can improve the motors performance? Is there anything else to the electrical system that I should investigate? I think tomorrow I will put the old plugs back in, and try to readjust the carb needles, and run the motor longer.

 

[rgnjc]

No Title

Adding these pics.

 

[F_R]

It certainly sounds like the carburetor may need adjusting. If that doesn't fix it, are you SURE it is running on both cylinders? Can we assume you removed the accessory ground from the ignition switch? I guess you know that is what blew up your coil. You can eliminate the wiring as a possibility by disconnecting both small black wires that come from under the mag plate. Warning!! you won't be able to shut it off with them disconnected, and it may run wild if you rev it up over idle in neutral. On second thought, disconnect the wire running between the vacuum cut-out switch and junction box, plus the other mag wire leading to the junction box. Leave the rest of the wires connected to the vacuum cut-out to prevent running wild.

As long as the electric starter is working, there is nothing wrong with the solenoid, so get that out of your mind.

 

[Tim Frank]

I would clean and re-gap the points.
Sounds like you were running 12 volts through portions of your ignition system.....that never ends well. Might have been some arcing across the points and that could be an issue.
Easy to eliminate that as a contributor.

 

[rgnjc]

No Title

Took the flywheel off yesterday, one of the points was completely covered in grease/oil. I put a little on the flywheel shaft pin (not sure what its called) and I must have dripped some onto the point in the process (see pic).

I tried to replace the points since I had a replacement kit on hand, but the new points wouldn't close completely. So I was only able to replace half of each point. Anyway, I cleaned the other half, rechecked the gaps and the boat ran great on the lake today. It did have a little trouble at idle rpms when in gear or neutral, but I'm sure its because the carbs need readjusting and it was too late in the day to get into that.

 

[racerone]

No grease is to be used when installing a flywheel.----Must be clean and dry !!-----Have never seen a set of points on these that would not close either.---Did you try adjusting with the little " offset " adjusting screw ??

 

[F_R]

Agreed, NO grease or oil or anything else on the tapered shaft/flywheel. Furthermore, the nut MUST be torqued to 100-105 ft/lbs. Do any of this wrong and you run serious risk of destroying the flywheel AND crankshaft. When that happens, it is all over except the burial.

There have been reports of points that do not close. They are defective. Take them back to the store.

 

[rgnjc]

OK thanks, I actually ended up wiping it all off and cleaning it, after deciding that it didn't seem like a good idea. The logic behind it was, in my tune up kit came a little capsule of grease in it, which I assumed was to be applied somewhere there. Not knowing where to apply that I made a wild guess, which I thought about and decided against it.

Also, the one point would not close regardless of the adjustment screw's position. The other one I got did close, so it was only 1 of the 2.

 

[racerone]

The grease was to be used on that little felt pad ( if still there ) used to lubricate the rubbing blocks on the points.

 

[HighTrim]

You take the pill of grease, and lower it onto the rod before installing the points. I use a light oil, just a drop, like sewing machine oil, or 3 in 1, for the felt pad.

I hate to name names, but have had a few sets of Sierra points lately that were impossible to adjust. 1 of them, the rubbing block was not thick enough, so could not get them closed enough. Poor quality control. Use OEM points.

 

[rgnjc]

You take the pill of grease, and lower it onto the rod before installing the points. I use a light oil, just a drop, like sewing machine oil, or 3 in 1, for the felt pad.

I hate to name names, but have had a few sets of Sierra points lately that were impossible to adjust. 1 of them, the rubbing block was not thick enough, so could not get them closed enough. Poor quality control. Use OEM points.

This was exactly my problem, the one point that I was unable to close no matter how I adjusted it had a very large rubbing block relative to the old ones and the other new one that did fit. These were Sierras. The two new ones probably differed by 1 millimeter, which was enough to make the one with the larger block not want to close.