All electrical connections should be wire brushed clean and without any oxidation or anything that will prevent the current flow. The starter grounds through the frame connections to the battery and can sometimes not make a good connection so you can check the starter grounding by using a jumper cable with clamps to connect the ground post of the battery directly to the bolt that holds the starter to the bell housing of the tractor. If the direct connection with the cable improves the performance, you have a poor ground somewhere. StanGourdo wrote:....I am not sure how to check the grounds. Thanks everyone
EDIT: Reviewed this entire post and seen nothing about checking the battery ground connection. OEM connection was through the battery box and your 1949 cub might need a thorough cleaning of the grounding system. You can try moving the ground cable to a more direct ground on the tractor frame like one of the bolts on the transmission shifter cover.
