I bought an old mower with a 6.5hp motor a 123ko2-0479 0501295817179. Anyway is there supposed to be a spring on the choke linkage? if so what size? The other end, under the shroud, is the vane supposed to go behind the bimetal arm or in front? I tried sears parts direct chat and they sent me a link to a diagram of the block, no help there. This mower will start and die. appreciate the help.