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1. Check to make sure that rear of prop hub clears shoulder of crankshaft snap ring groove by at least .010. Rear of prop hub may be filed or sanded to get more clearance.

NOTE: On GPASC cranks, hub goes to .010" before brass drive gear.

2. Prop Hub should seat firmly onto crankshaft without the bolt. If Hub rotates on crankshaft file or machine off several thousands from the rear of the prop hub until it seats firmly onto crankshaft. This is extremely important. If you have any questions, please call us at 402-493-6507.

3. To taper crankshaft, place hub in jaws and index the taper off the prop hub. You can then place crankshaft in lathe to cut and grind taper on crank. Be sure to lap when done.

4. With hub on crankshaft and large washer in place, measure the distance from the top of the washer to the end of the threads in the crankshaft. Cut bolt to length if needed. Make sure that bolt does not bottom out in threads.

5. Make sure that the taper on the crankshaft is 100% free of oil and dirt before installing prop hub. The woodruff key will have to be machined to fit the hub keyway.

6. Install prop hub assembly before case halves have been bolted together. Trial fit hub and bearing before applying case sealer. Check for free rotation.

7. Make sure that the Force One Main Bearing is lubricated prior to installing Force One Prop Hub. Do not use grease!

8. 20MM Prop Hub BOLTS should be torqued to 80 ft. lbs. Be sure to line up cotter pin hole in bolt with cotter pin hole in the prop hub. NOTE: 80 lbs. for 20mm bolt only, 60 lbs. to 1/2" bolt.

9. Drill prop hub bolt to match hole in prop hub, if necessary.

10. Install locking cotter pin through prop hub and bolt.

NOTE: The woodruff key will have to be filed down so it will fit slot in the Force One Hub and the sides will need rounding.

NOTE: The cotter pin hole in the bolt will most likely not line up with the holes in the prop hub. Do not over torque the bolt and hub. Remove several thousands at a time from the washer by grinding or sanding. Recheck bolt fit and torque frequently.


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