Had a mower that surged normal idle to low idle. Engine is the one where plastic carburetor bolts on to the gas tank. Replaced the old carburetor as it was very inexpensive. When I hooked up the linkage springs, now the throttle cable does nothing when set to choke or pulled back to low idle. Have no idea how this could happen. The two springs have little tension on them and from what I can tell this is normal. Anyone know what I have missed on this?