48’ cub low power, backfiring under load

[CashHartlen]

I have a 48’ cub that was bought by my great grand father brand new, he left it to my grandfather and my grandfather left it to me. It’s sat for 20 years semi restored and painted. I’ve finally got around to getting it back to running order. After sweating for hours with the trusty hand crank it’s up and running and idling perfectly. I cleaned the points and replaced the plugs and carb, set the magneto timing exactly on tdc by following a great vid on youtube. runs great but is very slow revving and has no power at all. Struggles to go up a slight hill in second gear. I have new plug wires on the way for it as they’re pretty bad shape, seems to have great compression. Wondering what I should look into next for the low power issue. The govenor seems to be working as it should also. When it starts to bog down it starts to backfire which has me even more confused. Any tips would be greatly appreciated

 

[CashHartlen]

I have a 48’ cub that was bought by my great grand father brand new, he left it to my grandfather and my grandfather left it to me. It’s sat for 20 years semi restored and painted. I’ve finally got around to getting it back to running order. After sweating for hours with the trusty hand crank it’s up and running and idling perfectly. I cleaned the points and replaced the plugs and carb, set the magneto timing exactly on tdc by following a great vid on youtube. runs great but is very slow revving and has no power at all. Struggles to go up a slight hill in second gear. I have new plug wires on the way for it as they’re pretty bad shape, seems to have great compression. Wondering what I should look into next for the low power issue. The govenor seems to be working as it should also. When it starts to bog down it starts to backfire which has me even more confused. Any tips would be greatly appreciated

Update after reading other pages I too realized I had the plug wires on the cap wrong. Now I have a slight misfire but has LOADS of power so I just have to figure out the miss. I pulled the plug wires off one at a time and it ran rougher with each plug pulled and I’m getting very strong spark from mag as the spark was jumping a 3/4 inch gap on the wire

 

[Glen]

Hi,
Good that you got the engine to run better.
The post for the number 1 spark plug wire is originally the top post on the magneto cap.
Then 3, 4, 2, going clockwise around the cap, looking forward from behind the cap.

 

[staninlowerAL]

The cub c60 engine is noted for sticking valves after sitting unused/not run for a while. You could have some valves that are not operating as they should. Suggest you add some lubricant like Marvel Mistry Oil or Seafoam to the system per label directions and work the engine some. It might run better as you use it. JMHO Stan