Polastorm propeller hub kit for Mercury, model F21, is a replaceable, rubber-cushioned hub kit with 15 splines. It is used for mounting compatible Polastorm propellers without an integrated hub on Mercury outboards and documented MerCruiser sterndrives.
The PolaFlex system places a replaceable propeller hub between the propeller shaft and the propeller. The hub/cushion component is made of brass and rubber, which connects the drivetrain to the propeller and acts as a cushion hub.
The kit consists of a cushion/drive hub, thrust washer, front washer, spacer, and nut. The parts make up the necessary hub and mounting kit for a compatible propeller.
Compatibility
The F21 variant is intended for 15-spline propeller shafts and a gearcase with a diameter of 4 3/4" (120.7 mm). The documented engine range is 90 CT–400 hp.
Mercury compatibility includes 90, 100, and 115 hp Command Thrust from 2014; 135 hp from 1987; 150, 175, and 200 hp from 1978; 220 hp from 1987–1988; 225 hp from 1980; 225 hp SeaPro/Marathon of all years; 250–400 hp, 2- and 4-stroke, from 1990 as well as Mercury 3.4 liter from 1984–1986. Years indicated with a starting year apply within the documented model overview.
Documented MerCruiser applications include models 1S, 1B, 1C, 120, 140, 145 DTS, 165, 228, 470, 485, 888, 898, 225S, 233, 255TRS, 260, 280TS, and 330TRS through 1982; MerCruiser 120–260 hp from 1983–1985; Alpha One Drive generation 1 and 2 as well as Bravo One and Bravo One X.
Cross-references
F21 is part of the same documented interchange group as EMP-102B, F21A, Solas RBX-102 and RBX-102B, Michigan Wheel XHS II 202, and Turning Point 701. Mercury 835257K1 is documented as a direct cross-reference. Additional Mercury numbers in the interchange group are 835257A1, 835257Q9, 835277A1, and 835277Q1.
Always check the engine/drive model, gearcase diameter, number of splines, and original part number before purchasing.
Key featuresModel F21 in the PolaFlex series
Replaceable propeller hub kit with cushion hub
15 splines
For gearcase Ø 4 3/4" (120.7 mm)
Documented engine range: 90 CT–400 hp
Hub/cushion component in brass and rubber
For compatible Polastorm propellers
Complete with hub, thrust washer, front washer, spacer, and nut
