39 B Mag problem?

[Pat80flh]

I've got an old B that has been sitting a long time, pistons frozen. I ended up pulling the head in the field, filling the cylinders with various, and letting it sit. I finally got around to dragging it down to the barn. I've got it so it turns, the bores look good, engine is super clean inside. I put it back together, set the valves to zero lash, so I'd be sure they close. Fresh gas, flows, cleaned the needle and seat, gas is getting to carb, but no discernible spark.
FB model J mag. I took the caps off, scraped the points clean, reassembled, mindful of the chamfered teeth. Found TDC of #1 compression stroke, installed mag. I can't get spark to the end of the wire. Not a spark tester, not a screwdriver near ground, not a bare hand on screwdriver. I can feel a pretty good jolt with my hand direct from the coil, with the top cap off when the impulse snaps, but can't get anything from the plug wire towers. I've got couple more junkers in the tractor graveyard, but a different mag,and swapping caps between and around makes no difference.
I'm not too familiar with magnetos, if it was a battery/coil distributor I'd say I had a bad cap and or rotor. Maybe a coil that's weak. But I get not a whimper, backfire, or snort.
One of my theories is that I'm not getting enough engine speed out of it. It's a pretty stiff pull still. What do y'all think?

 

[Butch(OH)]

getting jolted tells me virtually nothing,
some people are sensitive to it sone are
not, a FMJ in good shape should just about
put you on your knees. Have you tested for
spark with the caps off? hold a
screwdriver against the case and the tip
about 1/4 away from the high tension
copper strip. If it won't jump that gap
when the impulse is tripped then you have
issues.

 

[funky_g00]

First off if I
understand you correctly
tthe valves are snug
with no clearance? It
would be better to set
the valves at 20 or 30
thousands if your goal
is to have the valves
seal. Speed does not
matter on a mag if the
impulse system is
working correctly. Have
you pulled and inspected
the coil for cracks. I
have had that cause loss
of spark at cap but not
at points. A weak
condensor will do the
same thing. Did you
turn the mag backwards
and align the rotor up
with the #1 lug in the
cap? Did you align the
A or the C on the rotor
shaft with the marked
tooth in mag body?

 

[teddy52food]

I have the testers and a magnet charger to check it out if you care to send it.
Thanks.

 

[Pat80flh]

How much would such a service cost?

It failed to produce a spark as suggested by Butch.

 

[teddy52food]

I usually get $30 for labor unless it takes longer than expected. Plus parts of
course. Thanks E Mail is open.

 

[teddy52food]

Did you get my e mail reply?

 

[Pat80flh]

(quoted from post at 10:14:45 07/21/23) Did you get my e mail reply?

Got it, thanks

 

[teddy52food]

Nothing came yet????????????

 

[teddy52food]

Still nothing today Thurs.