Chrysler Force Impeller | Sierra 18-3030 Sierra 18-3030 Chrysler Force Impeller Sierra 18-3030 Chrysler Force Impeller Diameter 2-1/4 in. Depth 1-1/8 in. 6 Blade Brass hub insert - Shaft Diameter 7/8 in. Force Outboard, 85HP(1975-89) 125HP A,B & C(1981-88) Replaces Mercury 47-803630T Replaces Mallory 9-45001