Reply To: Throttle linkage slop

[Mumbles]

The 9.9/15 horse motors are notorious for developing slop in the throttle linkage but there is a way to tighten it up a bit without pulling the powerhead by using brass shim stock.

Once the tiller is removed, the snap ring, # 67 must be undone to remove the gear, # 65, and the shaft, #53. A large screw can be inserted into the pin, #107, to remove it before removing the gears # 52 and #109, if desired. The shaft has alignment grooves on each square end and can only go in its corresponding gear one way so the side without the grooves is the side which will get shimmed.

I can’t find any photos so I’ll try to describe it the best I can. The shim stock gets cut into a strip about 1/4″ wide and an inch or so long. An eighth to a quarter inch of one end gets bent over ninety degrees and inserted into the # 52 and 65 gears on the side without the alignment grooves before the shaft is installed. The bent end is what holds it in place. If the parts are really worn, a second shim can be installed on the other side without the alignment grooves. The thickness of the shim(s) needed will vary depending on the amount of wear but they shouldn’t be too thick to prevent the shaft from sliding in the gears.

This is my poor mans approach to solving this problem and I’ve been doing it for years with great success! I do have some of these motors apart right now so I’ll try and get some photos up later.