Max-Prop Classic Generation 2 (3 & 4 Blade) — Instruction Manual

Installation

• Supplied assembled for right or left rotation, with the pitch set at order if it was discussed. Parts are NOT interchangeable: with more than one propeller, never swap parts.

1. Fit the propeller onto the shaft like a fixed propeller. A properly fitted key has almost no side clearance and a very small clearance on top, so a key that is too tall cannot push the propeller off centre.
2. Tighten the nut and secure it with the two Allen head screws.
3. Fill the propeller with the supplied marine grease through the holes marked "GREASE" using the supplied grease fitting (illustrated steps 1 to 9 in the PDF). The central body must be completely full, with grease oozing from the rotating joints between the central part and the hub. Use only a grease approved by Max-Prop, which stays fluid for years and does not stiffen in cold water.
4. Move the blades into the feathered position with the rounded trailing edges aft (Fig. 4).

Before Launching

• Hold the propeller shaft and check that the blades rotate freely from forward to reverse with a light effort.
• In the feathered position the blades must be perfectly lined up.
• Confirm the propeller body is full of grease.
• Protect the propeller from galvanic corrosion with sacrificial anodes on the propeller and on the shaft.

Pitch & Rotation

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.

• If the engine does not reach the desired RPM, reduce the blade angle; if it exceeds it, increase the blade angle.
• Blade angle changes in 1 degree increments, about 7 % engine RPM per degree at the same boat speed.
• Rotation is judged from the stern looking forward with the engine in forward: clockwise = right hand "R", counterclockwise = left hand "L".

Changing Pitch or Rotation

1. Rotate the blades to the feathered position.
2. Unscrew the zinc screws and remove the zinc.
3. Unscrew the nut locking screws and remove the nut.
4. With circlip pliers, remove the circlip inside the aft hub ring, then take off the aft hub ring (the part that carries the zinc).
5. Pull the body (blades stay with it) 2-3 cm aft to open a gap from the forward hub. Rotate it to line up the reference mark on the forward hub with the rotation and blade angle you want (the manual's example: 18° R rotation, or 22° L rotation).
6. Slide the body forward to engage fully on the forward hub, keeping the mark lined up, and make sure the blades are perfectly feathered.
7. Refit the aft hub ring with its reference dot lined up on the RIGHT or LEFT scale stamped on the body.
8. Refit the circlip, tighten the nut and secure it with the locking screws, and refit the zinc with its 3 screws.

The extra download shows the same pitch adjustment as illustrated steps for the 3 blade propeller.

Propeller Use

• The propeller works automatically: put the transmission in gear and the blades engage in forward or reverse; they feather from the forward position when you stop the engine and lock the shaft.
• Best way to feather: power at 2 to 3 knots in forward, then kill the engine while still engaged in forward. A properly greased propeller feathers in a fraction of a second once the shaft stops freewheeling.
• Do NOT kill the engine in reverse: the blades stay in the reverse position and cannot feather. You can use this to drive a shaft alternator.
• Mechanical transmission: stop the shaft freewheeling by engaging reverse, only after the engine has stopped completely.
• Hydraulic transmission: shut off the engine while still engaged in forward; the remaining hydraulic pressure locks the shaft for a few moments, enough for the propeller to feather.

Never shift between forward and reverse at high RPM. Idle down and shift at low RPM, or the shock load can damage the teeth of the blade gears and cone gear.