1. Remove your old propeller.
2. Remove any burrs or debris on the shaft or in the keyway.
3. If using a shaft adapter, see the Shaft Adapter section.
4. Without the key in place, slide the prop up the shaft as far as you
can, and mark the point reached. Remove the prop.
5. Make sure your key fits in both the shaft keyway and the keyway in the bore
of the prop.
6. If the key doesn’t fit, rub the sides of the key on some 100-180 grit sandpaper
placed on a flat surface. The key should be a snug fit, but not a force it. To
ease installation, sand a 45 degree angle (chamfer) on each edge, but the
chamfers should be barely visible (about 1/64” x 45 degrees).
7. Place the key in the shaft keyway. Make sure the key does not extend past
either end of the keyway. If the key is too long, shorten as necessary by
sanding it, and chamfer the end. The top of installed key should project
parallel to the shaft.
8. Slide the prop on the shaft, engaging the key. If the prop does not reach the
mark you made in Step 4, the key has either slid too far up the keyway, or the
key is too high. In this case, first try repositioning the key. If that fails, sand
the top of the key.
9. Install the prop, again insuring that it reaches or exceeds the mark you made in Step 4.
10. Install the shaft nut or nuts. Most people over-tighten shaft nuts; 50–100 foot
pounds is plenty. That’s the equivalent of 50-100 pounds on a 12 inch
wrench. If using a thick and a thin nut, be sure to tighten the outer lock nut
while holding the inner nut. If using a single nut or a castellated nut, be sure
to replace the
If a Nylon adapter
is used the torque required is less than 50 inch lbs to prevent compressing the nylon.