1960's Johnson 40 HP prop size

[fishon71]

Hi can someone tell me for a 40HP Johnson 1961, what is the standard prop size I should be using? Where do I start anyway?

 

[Paul Moir]

Re: 1960's Johnson 40 HP prop size

The "standard" prop was a 13.25"p. There are a number of options - all the way up to 14" and all the way down to 11". What have you got on it now? What sort of boat is it going on? <br /><br />If you can locate a local outboard junkyard, they'll have piles of props that fit these. They can be really handy for testing before laying out good money for a new prop. I think you'll likely be looking at a 13" or 14" rather than the stump pullers.<br /><br />Don't tell me you've come over to the Big Twins!

 

[sschaefer877]

Re: 1960's Johnson 40 HP prop size

I have a 16 foot starcraft with a 40 h.p.johnson. The 13 pitch works well for me.

 

[fishon71]

Re: 1960's Johnson 40 HP prop size

So I have a 10 3/8 X 13 1/4 does that sound about right? No sure how to read the numbers pitch/diameter ????

 

[Paul Moir]

Re: 1960's Johnson 40 HP prop size

On most my old ones, there will be a part number like 3xxxxx just behind the washer behind the drive pin. If the number is still legible, we can figure out what pitch it is.<br /><br />A prop shop can measure the pitch. I've done it successfully myself but you really need to set up a jig which requires some odd parts & tools. As for the one on the engine right now, no-one can be certain.

 

[rolmops]

Re: 1960's Johnson 40 HP prop size

10 3/8 x13 1/4 is what the early sixties 40 horse engines came with from the factory.Dependent on the shape,length and weight of your boat it may be perfect for you.Your WOT should be 4500rpm and that is what you should aim for.A tachometer on your boat is a very good idea.