To change a centrifugal clutch, loosen and remove the old clutch, and install and inspect the new clutch. During the replacement, do not apply any pressure on the bell housing or it will bend and destroy the clutch.
- Lubricate the shaft and clutch faces
Use a loosening lubricant on the shaft and clutch faces to get oil between the shaft and clutch, making the clutch easier to remove from the engine shaft. Clutches tend to get stuck tight, so soaking overnight is beneficial when possible.
- Loosen the retention set screws
Use an Allen wrench to loosen the two retention set screws.
- Press on the hub
Use a puller, if available, or a screwdriver to press on the hub (the solid part of the clutch closest to the engine). If you are using a screwdriver, use a piece of wood as a cushion between the screwdriver and the engine; this prevents damage to the motor and acts as a fulcrum to pry off the clutch. Remember to avoid putting pressure on the bell housing to prevent damage to the clutch.
- Remove the old centrifugal clutch
Gently pry the clutch away from the engine and off of the shaft.
- Apply an anti-seize compound
Prevent the shafts from rusting together by applying an anti-seize compound to the engine crankshaft before you mount the clutch.
- Attach the clutch
Be sure your new key is the proper size. Use a hardened 1 1/2 inch OD flat washer with the proper size grade 5 bolt and lock washer to securely attach the clutch to the crankshaft. If you have a torque wrench, torque the bolt to 14 to 19 foot pounds for 5/16 to 24 UNF threads or 26 to 35 foot pounds for 3/8 to 24 USF threads. If necessary, install a spacer so that the clutch secures to a square shoulder to prevent the clutch from pushing onto the crankshaft chamber.
- Inspect the new centrifugal clutch
Before you start the engine, check that the clutch drum rotates freely on the crankshaft. If it doesn't, you must replace the drum assembly.