Re: ’57 Golden Javelin – fuel consumption question

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auldscott

US Member - 2 Years
Replies: 175
Topics: 42
#79117

I guess the matter of optimizing propeller selection, motor tilt, and motor height could be more or less dismissed as long as the boat runs, but motors are designed to run at a certain RPM range at full throttle: too low, and the motor doesn’t make the power (especially true with two-strokes) and too high, the motor’s internals are stressed beyond design limits. There may also be a fall-off of power, but it depends on induction and exhaust tuning.

The limiting factor in smaller and older motors is that the selection of propellers is usually small. That said, in the heyday of Michigan Propellers there was a pretty wide selection, which suggests that yes, many people did measure RPM and speed with propeller changes.

Owners of larger, more powerful boats pay close attention to propeller selection, to the extent that every combination is well tested.