Largest diameter prop for alpha one (first gen)

Benny67

Chief Petty Officer
Joined
Apr 21, 2015
Messages
571
Does anybody offhand know the maximum diameter prop I can put on my drive without it hitting? I have a 14.25" diameter now and want to jump to 15" before I buy I want to be sure it will accommodate a 15" prop.

I have been trying out a few props to get the correct setup and wanted to install a 15x19 prop on my 26ft cruiser. The prop I have on it now is 14.25x21 it's not allowing me to rev past 3400 rpm. The boat runs great with the 21" pitch prop and I almost never cruise over 2900 rpm but I know it's lugging the motor and I want to get it corrected before any damage occurs.

I found a prop calculator online and with the specs I put in it recommends a 16.1 x 18.6 pitch to achieve my desired results. Mercuiser makes a 15x19 prop...I believe it should do most of what I wish for it to do.

I tried out a 13.25x17 prop and it didn't allow me to run over 13mph but I could rev the hell out of the engine. The 15x19 sounds like the best bet to me based on all the factors I have investigated.

My setup is 88 5.7 Alpha one with 1.47 ratio (260hp)

any input?
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
The outdrive will handle at least a 16" diameter. You may have to modify or replace the anode
 

Benny67

Chief Petty Officer
Joined
Apr 21, 2015
Messages
571
Thanks for the info.

I have a flat magnesium in it now so I should be good to go
 
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