Condenser.

[Lilduke88]

So I’m having a issue getting my cub to start, i have power to the distributor but when I look inside at the points it is not getting a spark every time it opens. It might spark every 4th or so tie it opens. Is this a bad condenser or something else. I cleaned them off and when I do get a spark that carries to the plug it seems pretty weak. I need to almost touch the plug to the block to see the spark.

[Glen]

Hi,
The points need to have flat and shiny surfaces to work best. File them flat is the best way, unless you put in new points. Wipe off all filings with a clean rag.
I take the points out and set them on a solid surface to file them.
Then you would need to set the gap.

If it is not the points causing the problem, it could be the condenser or the coil.

It's cheaper to replace the condenser first.
The original coils on Cubs commonly quit, partly or fully.

There is also an insulation in the side of the magneto, or Battery Ignition unit that can crack, or break, then it can short there. Be sure it is good.
Below is a new one at TM Tractor, you can look at the pics.

http://www.tmtractor.com/new/el/957fp.htm

Below is a listing for new points and condenser, showing the style of condenser they use.

http://www.tmtractor.com/new/el/367fp.htm

The system should make a blue spark that jumps about 1/4".

[Dale Finch]

I have also had the "rub block" (not sure the official name!) wear or break, so that the gap was inconsistent. So while you have it open, check for that.

Another problem could be the insulator to which the spring side of the points is attached...could be broken, allowing some movement or misalignment of the contacts.

[Gary S.]

Might just be a good idea to give it a tune up anyway especially if you don't know or don't remember when it was last done. Since these parts are not made in the quantities they used to be the quality just isn't there anymore. Many are plated rather than being solid and don't like to be filed. I recently had a bad Echlin condenser for a Ford V8 go bad in 5 minutes of running.

[Glen]

I cleaned them off and when I do get a spark that carries to the plug it seems pretty weak. I need to almost touch the plug to the block to see the spark.

Hi,
If you are checking the spark by removing a spark plug, and connecting the wire to it, you have to ground the bottom area of the spark plug to a bare place on the engine for it to show a spark.

[Lilduke88]

That is what I did. I took a plug out, put it in the spark plug wire and touched it to the bolt on the block.

[TallCoolOne58]

Least expensive best place to start is a good tune up, with quality points and condensor. Solves 90% of no start problems due to ignition.

If not, you'll have to work your way back from there, checking coil for continuity and resistance etc. You say you have juice to the coil. Is there juice on the other contact leading to distributor when the points are closed?