1976 Johnson 40hp best prop

[aaronlee]

Wondering what the best prop is for top speed with my motor. It's on a 15 ft tri hull boat

 

[gm280]

Re: 1976 Johnson 40hp best prop

That can only be determined with a tachometer and a GPS speedometer for any boat setup. You can't simply state one size to accomplish the best without see all the info about engine RPMs and speed developed...

 

[aaronlee]

Re: 1976 Johnson 40hp best prop

Yes it has all that 5000 rpms it goes around 22mph now.

 

[jestor68]

Re: 1976 Johnson 40hp best prop

With a Wot rpm range of 4500-5500 rpm, it looks like you're about right at 5000 rpm(the rated hp rpm).

It really depends on what you're looking for. If you want more power to pull a skier, you'll need to drop pitch. For general running around, you're fine.

The OE number for the 13 pitch is 0384460. For the 11 pitch, it's 0385955.

Michigan makes a couple of props(listed in the prop section) for your motor in 12 and 11.5 pitches.

Be advised that the OE OMC props are fast disappearing ( like 3 or 4 in stock in a couple of places I looked at).

 

[steelespike]

Re: 1976 Johnson 40hp best prop

Yes it has all that 5000 rpms it goes around 22mph now.

We need your prop size,usually near the base of the blades or on the hub.
Lightly loaded top speed would require a different prop than the whole family and gear or for the best water sports.