dennisomfs
New member
Having a real dilema finding a prop for a Force motor on a used boat I recently purchased (with no prop) to put on small lake. The 15' astroglass boat (1986) and 40hp 2 stroke motor (runs good with all new hoses) seemed about right. However, none of the boating 'experts' seem to be able to help find a prop. I've already ordered and returned two Solas props that I thought were correct. I do not have a serial number plate on engine as at some time in past the front steering arm connection was broken and a new section welded in place. Only numbers are on the engine stamped into metal... one is R574791, another is WB 110A333, another is 820198. The cowling says Force 40 by Mercury Marine. Control at side of boat says Quicksilver and also appears to be a replacement. The largest diameter prop that will work is 11" maximum to clear the horizontal stabilizer. The prop shaft has a total length of 3 1/2" which includes 1/2" for the nut and cotter pin, and 2" for the splines with a total of 14 splines. The diameter of the shaft is 11/16". I can find no info on a 40 HP merc motor that has 14 splines except those under 20hp, and then no info on shaft length or diameter to try and match up something that would work. guessing a midrange pitch would work but right now just want anything that will get boat in water. Would a different hub and lower unit work ?? What would be needed for that? I hate to just dump the entire motor since it is clean and in good working order despite its age. Any help or suggestions would be appreciated...DRSpence