[Jimbird89]

I'm working on a '72 LB 5239A. D-408. I simply cannot get a spark out of it. New coil, new points/condenser, new plug wire, new plug, etc. I have checked the point gap three times and it's within spec, the coil air gap is good. No spark with or without the plug. The flywheel magnets are a bit rusty from the mower sitting outside for around 20 years, but I sanded them to the best of my ability and they are still strong. What am I missing?

 

[Lawnboy77]

Check for a short to ground from the wire at the condenser to the on/off switch grommet. Just check for continuity at that wire to ground, if you have continuity then that is the culprit. Might not hurt to replace that wire if it looks like the original one, if it is the original, the insulation is probably very brittle and most likely has some chaffing where it exits the points/condenser enclosure. I found that part of the wire had chaffed through to bare wire on the D400 in the pic, so I put a small piece of heat shrink right there to help prevent it in the future.

 

[cityboy]

I agree, I was thinking a ground problem some where.

 

[rscurtis]

Make sure you have the spark advance weight installed correctly. "Shaft keyway this end".

 

[Jimbird89]

It turned out to be a bad set of points. The contact on the non-springy side of the points was loose and not staked properly. New set of points and it fired right up...now I have to figure out the carb problems. It's running WAYYY too rich and even with the adjustment needle closed, it runs rich. It leans out right before it runs out of gas and runs great.

 

[4x4_Welder]

Sounds like the float level is too high.

 

[Lawnboy77]

Sounds like the float level is too high.

either that or fuel is being pulled up through the primer, may need to replace the seal on the primer plunger.

 

[Jimbird89]

either that or fuel is being pulled up through the primer, may need to replace the seal on the primer plunger.

I think you hit it! I was thinking it was the float. I pulled the bowl off and found the float a bit dark and heavier than I thought it should be. Replaced it with a known good used one and set the level. Fired it up and it was still the same. It has to be the primer seal. The primer doesn't seem to work very well to help with starting, so there's a good chance that it's bad. It is 40 years old, so it's due to be replaced. Thanks for that hint, I was not aware that this could result in an over-rich condition, but I knew it had to be something stupid that I was overlooking.

I'll put up a picture of this mower soon. It's camoflage from sitting outside for about 20 years. Some paint worn off, some rust stains on the deck that came from the handle, the shroud is faded. Still has all 4 original green wheels in great shape though. It looks bad, but it was well preserved mechanically because it was abandoned and today was the first time in roughly 20 years that it ran.

 

[echoman]

I've got a couple new primer/plunger kits I can sell if you need one jimbird89. Let me know your part numbers as I think the original numbers are still on the bag they're in. Pretty sure what I have is what you need. Don't do much work on any 400 series. A bit on the 600's.

 

[Jimbird89]

I happened to have a carb kit with a new plunger. The old one had to be cut off because it was staked/riveted on both ends...not pinned on at the top like the replacement. Anyway, put all the new stuff in the carb and fired it on the first pull. Runs pretty good, but still needs some minor adjustments and probably seals.

Anyone want to adopt this mower and restore it? It's pretty ugly, but it's all there. My camera wouldn't focus properly, so the picture isn't great, but you get the idea.