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Prop Bolts:
It is vital and completely necessary for every wooden prop to be RE-TORQUED, inspected and tracked at every service (50 hours). Tracking to be within 2mm at the tip. We have seen so many cases in the past of “loose” props. Iron “stains” radiating out from the hub are a dead give away to prop tension. Movement of the prop “at each power pulse” sends messages down the crankshaft. The last part to receive that “all is not well” is the flywheel. If at any time a prop strike has occurred it is very wise to replace the flywheel bolts. This can be done one at a time with the correct procedure. It is an easy procedure to conduct a preliminary prop balance if prop vibration is evident. Usually all that is required is to spray some more “clear” over the tip section of the lightest blade to effect good balance. At the other end of the spectrum adding appropriate ballast weights maybe needed. A light sand to the area being sprayed will give a better adhesion. Prop tracking should indicate no more than 2mm difference between blades before a problem can exist. Some props showing a bit of age might need a few layers of glass on the prop hub face. If this is neatly done, and carefully sanded, it will bring a prop of poor tracking to one within limits. The resin to use is usually “Polyester” type, but definitely not epoxy. Epoxy is heat sensitive and you guessed it—and with a hot crank, the result would be distorted epoxy and a prop no longer tracking correctly. Power With the latest engines giving increased HP you may require a higher pitched prop. Engine will on standard prop indicate 2800—2900 on take off and rev out to 3200-3250 at full throttle.
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