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Old 05-14-2010, 05:39 PM
volkswagen50 volkswagen50 is offline
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small outboard prop question

On a small outboard motor, say 5-6 hp two stroke, whats the prop speed vs/engine speed? Are they geared down? Are 4 strokes geared different, I'm thinking that four strokes do not rev as high as a two stroke would at max speed.
What does a small outboard like that turn for rpm??
Thanks!
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Old 05-14-2010, 06:40 PM
Jango Jango is offline
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I believe Max Motor speed for both the 2 stroke and 4 stroke is 4500 - 5500 rpm with 2:1 Gearing. i.e. Prop running half speed
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Old 05-15-2010, 06:20 AM
capt littlelegs capt littlelegs is offline
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2:1 won't be far out, for example a Yamaha 30 is 1.84:1, the deciding factor is the crownwheel and pinion size in a slim gearbox.
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Old 05-22-2010, 09:45 AM
jonr jonr is offline
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Some of the 4 strokes I've seen rev a little higher than the equivalent two stroke.
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