Finding out a gear ratio

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Finding out a gear ratio

Yes, just turn the engine (By Hand) with the drive in gear until the prop shaft makes one complete revolution (Exactly) it should take 1 and one half revolutions to turn the propshaft 360° if you have a 1.50 drive.<br /><br />It is usually stamped on the port side of the drive, but that really doesn't mean someone hasn't changed the gear ratio.
 

superiormgmt

Seaman
Joined
May 13, 2004
Messages
53
Re: Finding out a gear ratio

The drive is for a boat I'm building and my engines are not in yet. I did not notice a stamp but I'll be able to tell eventualy. Thank you Mr.S
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Finding out a gear ratio

Then just turn the input shaft of the drive 1.5 turns. <br />The input shaft is hooked directly to the crank so it's the same rpm as the crankshaft.
 
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