Hi,
Jim B. has said on here if the oil filter cover leaks, try loosening the bolt slightly, and turn the cover some, tighten the bolt and run the engine, and see if it stops leaking.
Repeat that if needed.
If you mean the copper washer under the oil filter cover bolt head won't stop leaking, I have needed to put a little sealer on the bolt washer.
I used Permanex Aviation Form A Gasket.
They sell it at NAPA here in the west.
Stir it before using, it can settle in the can sitting.
If the large gasket under cover is squishing too much, and it is rubber, people have said on here that they don't work well. They couldn't tighten the cover enough, and the rubber gasket squished out.
They said to buy the paper gasket, then you can tighten the cover without the gasket squishing out.
Below is a listing for a gasket at TM Tractor. I'm not sure if it's paper, you could ask them.
Case IH had the paper gasket in the past, they might still have it, I haven't asked lately.
http://www.tmtractor.com/new/en/136fp.htm The starter on a 1968 Cub should be the Delco 12 volt starter. IH changed Cubs to 12 volts in mid 1964.
The starter is different than the 6 volt starter.
Below are pics from TM Tractor.
http://www.tmtractor.com/tm-tractor/gel ... 2v_001.htm You could try oiling the spline the starter drive moves forward and back on. Use light motor oil.
Turn the starter gear forward and back on the spline, and see if it works without being tight on the spline.
I suppose the drive has a spline, I haven't seen the 12 volt starter in person.
Below is a page from the Cub parts manual showing the 12 volt starter.
http://www.farmallcub.info/manuals/cub_ ... 008-11.jpg I would buy a flat set of feeler gauges and set the point gap, if you didn't set it with a feeler gauge.
It's important they have a .020" gap.
I would set the timing with a timing light. The Cub service manual says set it with a timing light. Then you know it is right.
The engine can start good, but the timing can be off, then the engine can have less power than it should.