Merc 1000 prop and gearing

[Purdy1]

I have a 1969 Merc 1000, I am looking to change the lower unit gearing and prop. I have the choice between a 1.7:1 ratio and a 2.30:1 ratio. As well I have a 25 pitch chopper prop and a 22 pitch 3 blade prop available. I am putting the motor on 12 foot Humber Jewel. I am looking for the combination that would produce the best top speed for this boat and motor combo. Thanks

 

[steelespike]

Re: Merc 1000 prop and gearing

Motor came with 1.7:1You want the 1.7.Motor is rated for 5,300 rpm.
Set the motor up as high as it will go without ventilation(cavitation) issues.
try the 25 and go from there.You might go to Johns Old Mercury Web Site
and explain your setup and see what rpm they run a 1,000 at.They may have a prop suggestion as well.