Ignition problems on 65 Landlord

[MrSteele]

OK, a question for those folks who know points and condensers. This one nearly drove me crazier that I was. First, let me say again that I do not wish to install electronic ignition, though it would likely save me a bunch of time. What it came with, it still has, and will continue to have. The engine is a bit later model, 1968 cast iron, 10 HP. I used the mower back in July and early August with no hiccups, put gas in it, choke, let the engine turn over less than twice, and we were ready to go. Last week, I got ready to cut the yard, and, engine turned over, nothing.. I checked the fire, nothing. Took the cover off and cleaned the points, nothing, so I decided it was a condenser. Put in a good, new condenser, still nothing. Next morning, I ordered parts. While waiting for parts, decided to check again. Started right up and cut the back yard. Shut it down, drank an adult beverage, and nothing, no fire. Got aggravated yesterday, worked into the evening trying to decide where to look next. Checked grounds, checked to make sure nothing was grounded that should not be under the cover, made a new kill wire that I knew would not ground with the cover in place, put it all together, and nothing. Getting close to dark, I took it apart again, turned it over and found the problem. Made it go away, and have been cutting grass all day. What was the problem?

[BLT]

The only thing you  haven't verified is the ignition switch itself. Make up a separate short grounding wire to replace the switch wire and see what happens. New wire only has to be 6-8" long just to short out on block.

 

[fishnwiz]

Ground issue IMO.

[MrSteele]

OK, Maybe I did not say enough. After I found the problem, the tractor started and I used it yesterday all afternoon with no problems, started every time I asked. Nothing wrong with the switch, though I forgot to say I checked it. Was a ground problem of sorts, but where and what?

 

[MikeES]

Points cover grounding something out, or the little plastic/bakelite tab broke and the screw on the kill wire was grounded.

[fishnwiz]

5 hours ago, MikeES said:

Points cover grounding something out, or the little plastic/bakelite tab broke and the screw on the kill wire was grounded.

This is a great place to start as I have found this to be a problem area on several different tractors I have worked on.

Edited August 30, 2017 by fishnwiz

[MrSteele]

Everything was connected, nothing broken, but the insulating tab was out of place. It moves until the screw is tightened, and had swung up only slightly, allowing the fire to jump from the base of the points over to the screw. Not really a ground, but a short circuit. The insulator was in such a position as to allow the system to work sometime, but not all. Had it not been dark when I was working on it, I would never have seen the fire jumping where it was not supposed to. Before Sunday night, I had only worked in daylight.

A trick I use on the points covers is to cut a small rubber grommet so that it will fit and still allow the wires to pass through. Of late, I have added a shrink wrap sleeve over the wires, as well, but do not shrink it. Sometimes, as a just in case, I have used electrical tape over the gasket in case the insulation was broken. The shrink wrap sleeve is easier than the tape and always stays in place. Testing the switch is easy for me. My kill wire is only about 6" long coming out of the cover. I have a spade end soldered to it, with a female end on the tractor. To test switch, simply disconnect. The tractor was rigged thus when I got it, thought it was a good idea, though I soldered all connectors to the wires instead of crimping

[PhanDad]

Very interesting.  Would definitely be a hard issue to track down. 

I am curious about one thing though,  You mention " insulating tab ... had swung up only slightly".  This statement makes it sound like the insulating tab is mounted on the bottom screw of the points cover.  On all Simplicity/AC tractors with Briggs engines I have had, the insulating tab is mounted on the top screw as can be seen in these pics (best pics I have, the tab is behind the fuel shutoff valve in one pic and the behind a wire nut for the Megafire conversion on the other):

 

If I remember correctly, there's a small "ledge" on the points cover that the tab sits on that can be seen in the second pic. 

Is your points cover/insulating tab "upside" down compared to these?

[MrSteele]

I had already had a problem with that particular tab  , so I made a short lead with the connection away from the cover itself. The tab I am speaking of is the insulator built onto the points that the screw holding all the wires is mounted to. The wires attach to a piece of what appears to be brass in color, mounted on insulation. The tab can swing up or down. In the up position, the short to ground may or may not occur