prop pitch ?

[jsiedentopf]

I know , not another prop question. But I did search, I have a 1970 Johnson 40hp on a 1966 lone star runabout. I currently has a 12 pitch prop and wont come up to plane , I don't have a tach but at wot it is far from its peak output. My local boat guy has recommended a 10 pitch or even a 9. Problem is I cant find one in a 10 3/8 diameter. how do I find the right pitch for my boat. I am tired of it dogging around the lake.

 

[Frank Acampora]

Re: prop pitch ?

Michigan made a 10 3/8 X 11, 3 blade for Chrysler engines. I believe it was the same prop as your engine takes with a different hub. You have a two piece lower unit don't you? You can get one on e bay and re-hub it. That may help some.

 

[WillyBWright]

Re: prop pitch ?

They are common pin-drive Johnson/Evinrude propellers that fit 35-40Hp from the late 50s to mid 70s. They're real easy to find used. I'll bet eBay has a bunch right now in both bronze and aluminum. Diameter is going to vary by pitch. Diameter increases as pitch decreases...by fractions of an inch usually.

 

[jsiedentopf]

Re: prop pitch ?

thanks i will check on ebay, I am also going to call michigan wheel and ask them.

 

[Sailor77.7]

Re: prop pitch ?

jsiedentopf,

you might want to look at the following url:

http://www.oldmercs.com/

I know that it says oldmercs, but they also deal with old Johnsons and some others that go back to the 60's and earlier. You might be able to find out what you want to know there.

Vr,

sailor77.7

 

[steelespike]

Re: prop pitch ?

I know , not another prop question. But I did search, I have a 1970 Johnson 40hp on a 1966 lone star runabout. I currently has a 12 pitch prop and wont come up to plane , I don't have a tach but at wot it is far from its peak output. My local boat guy has recommended a 10 pitch or even a 9. Problem is I cant find one in a 10 3/8 diameter. how do I find the right pitch for my boat. I am tired of it dogging around the lake.

Unless your really hauling a load you need to confirm the condition of your motor.If it won't plane that boat something is up.low compression,missing on one cylinder,throttle not opening all the way.9 inch pitch is something you would find on a pontoon which are very hard to push.