03 Johnson 40 hp 2 stroke prop size and pitch?

[rdl1642]

Hello folks. New to the forum. I have I believe an 03 (manufactured 8/02) Johnson J40PLSTD 2 stroke 40 hp outboard motor on a Lowe 16’ aluminum deep v fishing boat (side console). I currently have a 3 blade 12 1/4” x 15 aluminum propeller on it. It runs great other than being a little cold blooded. It comes out of the hole almost instantly with no difficulty and according to the gps does about 25-27 mph on the top end. I don’t know what the rpm’s are at that top speed because that is the only gauge on my console that doesn’t work. I’m looking to give up a little acceleration in exchange for a higher top speed but (judging by ear only) don’t want to take my rpm’s much higher due to the age of my motor. Should I keep my prop diameter the same and go with a 17 pitch prop or lower my diameter as well? Any guidance/experience you could share would be much appreciated.

Randy

 

[racerone]

No such thing as a " cold blooded motor "----Often folks need to use the correct starting procedure.----Outline your procedure.----Or are you pushing the key in and HOLDING it in while cranking it over .

 

[rdl1642]

I squeeze my fuel ball a couple times, push the key in while cranking, once the motor starts I let go of the key. It usually dies after a few seconds and I recheck the fuel prime. Usually takes a few more starts before she is ready to stay running. Once it warms up each start after on the lake is pretty much instant.

 

[rdl1642]

My larger concern is the prop sizing.

 

[racerone]

Try a 17" pitch.----Using the wrong starting procedure can lead to a damaged starter.----And even more starting issues then.---Plus an expensive starter ruined.

 

[kevinj]

You can also use the Solas Propeller Selection Tool to enter your boat information and engine size and it will give you a recommended prop. I'd suggest getting your tach repaired because without seeing the exact RPM at WOT you're just guessing.