Hi folks,
I'm newbie in the Johnson motors and met the next problem:
Working through a full rebuild on this motor — carb rebuilt, fuel pump rebuilt, points gapped at .020, spark good on both cylinders. Motor starts and runs fine at FAST but won't hold a stable idle; throttle plate barely opens at SLOW/START positions.
Traced it to the armature plate not reaching its correct SLOW/START position — it reaches full advance fine (hits the mechanical stop at FAST), but on the low end there's roughly 1-1.5" of travel missing at the plate's edge.
Found two contributing sources of play in the throttle shaft (the vertical shaft connecting the tiller twist-grip's bevel gear down to the linkage that turns the armature plate):
I can't find any parts diagram anywhere (Crowley, marineengine, boats.net) that shows this shaft/socket assembly — it doesn't appear to be listed under Magneto, Carburetor, or Powerhead sections, possibly because it was never sold as a separate serviceable part.
Has anyone dealt with this specific joint before, or knows where to find an exploded diagram of it? Trying to figure out the correct fix — shimming the socket bore, or if there's a proper replacement bushing/shaft part number I'm missing.
Photos of the joint and the remaining gap attached.
photo-1 gap in the START handle posittion
photo-2 gap in the SLOW handle position
photo-3 joint
I'm newbie in the Johnson motors and met the next problem:
Working through a full rebuild on this motor — carb rebuilt, fuel pump rebuilt, points gapped at .020, spark good on both cylinders. Motor starts and runs fine at FAST but won't hold a stable idle; throttle plate barely opens at SLOW/START positions.
Traced it to the armature plate not reaching its correct SLOW/START position — it reaches full advance fine (hits the mechanical stop at FAST), but on the low end there's roughly 1-1.5" of travel missing at the plate's edge.
Found two contributing sources of play in the throttle shaft (the vertical shaft connecting the tiller twist-grip's bevel gear down to the linkage that turns the armature plate):
- ~0.65mm gap in the keyway (shimmed this already)
- Additional radial play of the shaft inside its socket, independent of the key
I can't find any parts diagram anywhere (Crowley, marineengine, boats.net) that shows this shaft/socket assembly — it doesn't appear to be listed under Magneto, Carburetor, or Powerhead sections, possibly because it was never sold as a separate serviceable part.
Has anyone dealt with this specific joint before, or knows where to find an exploded diagram of it? Trying to figure out the correct fix — shimming the socket bore, or if there's a proper replacement bushing/shaft part number I'm missing.
Photos of the joint and the remaining gap attached.
photo-1 gap in the START handle posittion
photo-2 gap in the SLOW handle position
photo-3 joint
