B won't start

[alderman]

I have a bn with a mower deck that I use
for my lawn. While mowing it started to
miss on a cylinder. I checked points and
they looked good. Rotor was worn quite a
bit and distributor cap had a looked
fine. I replaced the rotor and cap but
not points. Now no start. Wondering what
else? This has the h4 magnito on it.
Could the points be bad but still look
good?

 

[Red Dave]

Two things come to mind:
1, Yes, points can look good and still be bad. I would run a piece of sandpaper through them to make sure they are clean.

2, When you put the cover back over the points, did you make sure that you didn't get them out of time? It is easy to do. Make sure that the rotor points to the distributor post for #1 cylinder when #1 is at top dead center.

Beyond that, I'd also check the condenser.

 

[Bob]

You may have got debris between the points while you were in there, or perhaps something got shorted to ground in the points/condenser area.

Also, you didn't take the little cover with the two screws off and mess up the rotor timing, I hope?
Magneto service manual

 

[alderman]

I took the cover that goes over the points off as that is the only way to look at points. Other than that I didn't do anything. I'm thinking a sh
ort somewhere or condenser as couple times last summer I had an issue with it missing on a cylinder when I was in some heavy tall grass. After I let it sit for a while it would run great again. But hey...I'm just guessing and may be waaaay off base.

 

[Red Dave]

If you took off that cover, did you mark the position of the rotor and make sure that it was pointed the same way when you put it back together? If not, the rotor is likely out of time and that will keep it from running.

 

[gene bender]

Have you pulled the plugs and do a compression check mite need to change plugs aroundlike the one from missing cycl put in another cycl likeways with the wires. Mag is OK or it wouldnt fire other cycls. Not unusual to find a bad plug or wire.