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MDB	09-01-2005 11:48 AM

Changing Props not Lower Unit

I'm trying to figure out how to get a proper propeller for my soon to be re-powered boat without changing the lower unit of my SX leg. I went from a 3.0l to a 4.3l. Gear ratio is approx 1.97:1 currently. WOT should be about 4400 for the 3.0l vs 4800 for the 4.3.

Any ideas other than 200rpm per 1"pitch. How does the gear ratio affect RPM with a stronger engine same prop?

hillbilly24

09-01-2005 11:54 AM

Re: Changing Props not Lower Unit

What pitch were you running?

MDB	09-01-2005 12:08 PM

Re: Changing Props not Lower Unit

19"

East Coast B

09-01-2005 01:37 PM

Re: Changing Props not Lower Unit

Go to this BAM site and you can play around with plugging in numbers...

http://go-fast.com/Prop_Slip_Calculator.htm

What size and weight boat??

MDB	09-01-2005 02:11 PM

Re: Changing Props not Lower Unit

Will do! thx
It's a 20ft with cuddy...Apprx 3000lbs

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