Hello and welcome.
The 126 is the second rarest cub. Made from 69-71. I love mine and would probably never part with it. The serial number to determine the year should be on the rear differential not on the SG.
Your issue to me seems to be fuel related. I would start by cleaning entire fuel system tank to carb. Check or replace rubber lines that may be corroded from inside. Also. You may want to check under the engine tins and clean them out. Mice love building houses in there. Dirty tins will overheat and destroy these engines.
By the way. LETS SEE SOME PICS! 
__________________
Cooperino 100, 104,125, 126, 2x129's, 804, 1211, 1641
|