Max-Prop Classic 2 Blade — Instruction Manual
INSTRUCTION MANUAL
Pitch setting, gear-timing chart, assembly, feathering technique, greasing and troubleshooting for the Max-Prop Classic 2-blade automatic feathering propeller.
DocumentMax-Prop Classic 2 Blade Instruction Manual
FormatPDF · 12 pages · 1.0 MB
LanguageEnglish
Pitch Adjustment
Blade angle is adjustable from 10° to 30°. Find your diameter column, go down to the pitch you want in inches, and read the blade angle across. Too few RPM: reduce the angle; over-revving: increase it. A 2° change moves engine RPM 13%–15% at the same boat speed. Pitch is set with the propeller on the shaft.
| Blade angle | 12" | 13" | 14" | 15" | 16" | 17" | 18" | 19" | 20" | 21" | 22" | 23" | 24" | 25" | 26" |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 10° | 4 | 4.3 | 4.6 | 4.9 | 5.2 | 5.5 | 6 | 6.3 | 6.7 | 7.1 | 7.4 | 7.7 | 8 | 8.3 | 8.6 |
| 12° | 4.8 | 5.2 | 5.6 | 6 | 6.4 | 6.8 | 7.2 | 7.6 | 8 | 8.4 | 8.8 | 9.2 | 9.6 | 10 | 10.4 |
| 14° | 5.6 | 6 | 6.6 | 7.1 | 7.6 | 8 | 8.4 | 8.8 | 9.4 | 9.8 | 10.4 | 10.8 | 11.2 | 11.6 | 12.2 |
| 16° | 6.4 | 6.9 | 7.6 | 8.1 | 8.6 | 9.1 | 9.8 | 10.3 | 10.8 | 11.3 | 12 | 12.5 | 13 | 13.5 | 14 |
| 18° | 7.2 | 7.8 | 8.6 | 9.2 | 9.8 | 10.4 | 11 | 11.5 | 12.1 | 12.8 | 13.4 | 14 | 14.6 | 15.2 | 16 |
| 20° | 8.2 | 8.9 | 9.6 | 10.3 | 11 | 11.6 | 12.4 | 13 | 13.7 | 14.5 | 15 | 15.6 | 16.4 | 17 | 17.8 |
| 22° | 9.2 | 10 | 10.7 | 11.4 | 12.2 | 12.9 | 13.6 | 14.3 | 15.1 | 16 | 16.8 | 17.5 | 18.2 | 18.9 | 19.8 |
| 24° | 10 | 10.9 | 11.8 | 12.5 | 13.4 | 14.2 | 15 | 15.8 | 16.8 | 17.6 | 18.4 | 19.2 | 20.2 | 21 | 21.8 |
| 26° | 11 | 12 | 12.8 | 13.8 | 14.7 | 15.7 | 16.6 | 17.4 | 18.4 | 19.3 | 20.2 | 21 | 22 | 22.9 | 23.8 |
| 28° | 12 | 13 | 13.9 | 15 | 16 | 17 | 18 | 18.9 | 20 | 21 | 22 | 23 | 24 | 25 | 26 |
| 30° | 13 | 14 | 15.1 | 16.2 | 17.3 | 18.5 | 19.6 | 20.6 | 21.7 | 22.8 | 24 | 25 | 26.1 | 27.3 | 28.2 |
Values are pitch in inches, copied from Figure 1 of the manual.
Assembly
Hub, Nut and Gears
- Never swap parts between propellers: each one is individually balanced.
- Hub (1) must slide fully onto the shaft (2) with the key (3) fitted; mark the shaft without the key and file the key until the hub reaches the mark.
- Drilled nut: tighten the nut (4) and drill through nut and shaft for the pin (5); a cobalt bit helps.
- No-drill nut: align the grooves in the nut base with those in the hub, insert the pins (5) and rotate them clear of the cone gear.
- Only one thread may show aft of the nut; cut off any excess or it lifts the central cone gear (6).
- The groove on one tooth of the cone gear (6) is "X": seat it on the hub letter for your angle and rotation.
Blades and Spinner
- Blade letters A to K engage the • mark, L to Z engage the •• mark on the cone gear.
- Hold both blades on the spacer (9), fit one half-spinner (11) with numbers matching 1 to 1 and 2 to 2.
- Fill the second half-spinner completely with very fluid grease, fit it and all screws (12).
- Give spinner and blades a few bedding blows with a plastic or wooden mallet.
- Lock every screw with a cotter pin cut to 1/4", placed so a loosening screw hits it.
- Before launch: lock the shaft, check the blades swing freely forward to reverse, grease weeps from the joints, and the feathered blades line up.
Right Rotation
| Blade angle | X (–) hub | Y (•) | Y (••) |
|---|---|---|---|
| 30° | H | H | V |
| 28° | D | K | Z |
| 26° | V | B | N |
| 24° | S | C | P |
| 22° | N | D | S |
| 20° | K | E | T |
| 18° | E | H | V |
| 16° | C | K | Z |
| 14° | T | B | N |
| 12° | P | C | P |
| 10° | L | D | S |
| 0° | K | D | S |
Left Rotation
| Blade angle | X (–) hub | Y (•) | Y (••) |
|---|---|---|---|
| 10° | H | D | S |
| 12° | D | E | T |
| 14° | B | H | V |
| 16° | S | A | L |
| 18° | N | B | N |
| 20° | K | C | P |
| 22° | E | D | S |
| 24° | C | E | T |
| 26° | A | H | V |
| 28° | P | A | L |
| 30° | L | B | N |
Feathering
- Motor at 2 to 3 knots in forward.
- Stop the engine while still in forward gear.
- If the shaft still turns, engage reverse to stop it.
- Check: out of gear, a feathered prop does not freewheel. If it does, repeat.
- Never stop the engine in reverse: the blades stay in reverse pitch (this can drive a shaft alternator).
- Shift forward/reverse only at idle to avoid shocking the gear teeth.
Maintenance
- Regrease at least once a year; Lubriplate "130 AA" is recommended.
- Remove the forward set screw (#3 metric Allen), fit the zerc tower and pump until grease shows between hub and spinner; repeat at the aft hole until it shows between blades and spinner. Rotate the prop forward to reverse with each pump.
- Never leave the zerc tower in the propeller.
- Replace zinc anodes at least once a year and add a shaft zinc where possible; clean the end cap and zinc contact faces.
- Remove the prop by pulling only on the outside of the hub after removing spinner and nut.
- Saildrive: a ring anode cut in half and a notched thrust washer let you change saildrive anodes without removing the propeller.
Troubleshooting
- Stiff rotation: remove some grease from the spinner and reassemble.
- Hard spot (burr or ding): reassemble without the cone gear (6). If the hub is still hard, take 0.01 mm off surfaces "B" of the spacer with emery cloth on a flat file.
- Still hard points with the cone gear refitted: file 0.1 mm off surface (C) so the cone gear sits lower.
- Tapered bore machining: cut the keyway on the side opposite the pawl.
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