Max-Prop 3 Blade V.P. — Instruction Manual

Pitch Adjustment

A critical step: know the pitch to set before you start, either from your old propeller or from your engine and reduction ratio.

Fig. 1: pitch in inches for each blade angle (rows) and propeller diameter (columns). Size diameter and pitch as for a fixed propeller, find your diameter column, go down to the pitch you need and read the blade angle across.

• Pitch is adjustable from 10 to 30 degrees of blade angle.
• If the propeller does not reach the desired RPM, reduce the blade angle; if the engine exceeds it, increase the blade angle. A two degree change alters engine RPM by 13-15% at the same boat speed.
• On the V.P. the pitch is set on the adjustment ring, with the boat in or out of the water: pull back the ring, rotate it to the blade angle for your rotation, then push it back once the setting lines up with the degree reference mark. Example from the manual: 18° for a right-hand propeller or 22° for a left-hand propeller.
• The ring areas marked "very fluid grease" are the grease points on the body.

Assembly

Each propeller is individually balanced: with more than one propeller, never interchange parts. Assemble the propeller at least once before installing it.

1. A) Fit the hub (1) to the shaft (2). The key (3) must be the proper size and the hub must slide completely on: if unsure, mark the shaft without the key and file the key's sides or top until the hub reaches the mark with the key fitted.
2. B) Tighten the nut (4). Align the grooves in its base with the grooves in the hub to form two holes, insert the pins (5) and turn them so they do not interfere with the cone gear. One thread may show aft of the nut; cut any more off with a hacksaw, or it raises the cone gear (6) and affects performance.
3. C) Insert the central cone gear (6) into the hub: its "X" mark fits only where the hub has a gap in the gear teeth.
4. D) Fill both spinner halves (7) with grease (Lubraplate 130AA recommended), close them around the hub and tighten the screws. Do not use Teflon grease: it washes out very quickly.
5. E) Rotate the spinner until its "Y" mark lines up with "R" (right-hand shaft) or "L" (left-hand shaft) on top of the cone gear. Mark or tape spinner and hub: if the spinner turns before the blades are fitted, the blade angle changes.
6. F) Fit the three blades onto the three pins of the spacer (10), fill the end cap (11) with grease and seat the blades in it, matching numbers 1 to 1, 2 to 2 and 3 to 3.
7. G) Feather the blades with the rounded trailing edges aft, slide end cap and blades onto the spinner (numbers matching) and tighten the end cap screws. If the spinner rotated, pull the blades back 1/4" and realign the spinner and hub marks.
8. H) Give the spinner and blades a few bedding blows with a plastic or wooden mallet so the blades rotate more freely.
9. I) Lock each screw with a 1/16" stainless steel cotter pin cut to 1/4", placed so a loosening screw would hit it; spread the ends with a light hammer tap, not a screwdriver.
10. J) Fit zinc anodes on the shaft and on the end cap. Check the blades rotate freely and line up perfectly when feathered.

Stiff Rotation or Hard Spots

1. If the propeller does not rotate freely, remove some grease from the spinner and reassemble.
2. A burr in the gears or a dinged propeller can make blade movement hard. Reassemble without the cone gear (6) so blade and hub rotation are independent: if the hub is hard, remove 0.01 mm from surfaces "A" with emery cloth; if the blades are hard, remove 0.01 mm from surfaces "B" of the spacer with emery cloth around a flat file.
3. Refit the cone gear (6). If hard points remain, remove 0.1 mm from surface "C" with a flat file so the cone gear sits lower and the clearance between the conical gears increases.