#2 and #3 cylinders not firing?

I was hoping someone can help verify what is going on with my 1947 H. I've recently completed and overhaul of the engine. Upon initial startup in ran very well, nice and smooth, so I know it was timed properly and everything was working correctly. In the process of fixing a couple oil leaks I had to remove the magneto and re-install and re-time the engine. I've triple checked the timing so I think that is correct. The #1 and #4 are firing appropriately, but #2 and #3 are not. I swapped plugs #4 to #3 and #1 to #2 with the same result. #2 and #3 not firing. I swapped plugs back and swapped wires to verify its not a wire issue, had the same result,#2 and#3 not firing. I used an inline continuity tester and #1 and #4 the light was nice and bright, for #2 and #3, there was just a very weak light. My conclusion is there is something wrong with the magneto. Has anyone experienced this where the magneto doesn't fire just a couple of cylinders? I would think if it was going to fail, it would fail for all four. The magneto was rebuilt with the overhaul and has less than 10 hours of operation at this point. If it is in fact the magneto, is it possible it's an easy fix that I can do? Or will it need to be sent off for repair? Is there anything else I'm missing? Thanks for any help.

Phil
 
Did you check your firing order? Sometimes it is possible to accidentally reverse two wires and make the engine run quite poorly.
Zach
 
Very slight differences in the point gap between cylinders can cause issues. Set the gap .013" on a high point of mag cam. Check vap for cracks or carbon tracking. Jim
 
(quoted from post at 03:23:11 11/16/14) Did you check your firing order? Sometimes it is possible to accidentally reverse two wires and make the engine run quite poorly.
Zach

Yes I did check that, but will do so again to verify.
 
I agree with both posts. Be sure to check the firing order, 1342 when you are looking at the cap from the rear. You can turn engine with distributor cap off to make sure of the rotation of rotor. Lot of times guys get 2&3 in the wrong spot on cap. The other thing to look at is the point gap. Make sure it is the same on both of the cams. There are only two cams that open the points as it turns engine speed and the reduction to one half engine speed is in the distributor section. It is not unusual for one cam to be worn slightly more than other and that will give you a different point opening on one versus the other. So, make sure the closest one is at least .013.
 
Just where are the two cams that open the points on the H-4magneto. Ive been around those mags for 50 pluss yrs and i have never seen the second cam that opens the points.
 
Remove sparkplug & bring No1 piston near the radiator to TDC on the
compression stroke. Then see where your rotor is pointing. Should be at the No1 plug tower. Hal

2-1
4-3 As the rotor rotates CW.
 
2 lobes on the cam. One fires 1&4 the other2&3. That may be his problem, but I don't see why removing & replacing would change the point gap if it was running right before.
 
(quoted from post at 17:14:58 11/16/14) 2 lobes on the cam. One fires 1&4 the other2&3. That may be his problem, but I don't see why removing & replacing would change the point gap if it was running right before.

Checked wires, they were on correctly, adjusted the gap on the points, now the H is running appropriately. Obviously something did happen during removal. I appreciate everyone's input. Happy the H is running how it should again. Thanks!
 

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