Stainless Steel Prop - Johnson 1977 70 HP

johnjsa

Petty Officer 2nd Class
Joined
Mar 22, 2005
Messages
127
Considering getting a stainless prop for my motor, options are 13 1/4 by 17, 13 3/4 by 15, 13 by 19, 12 3/4 by 21 & 12 3/4 by 23. My motor currently has a 13 1/4 by 17 aluminum, what would your recommendation be as to size, pitch & prop model.
 

walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: Stainless Steel Prop - Johnson 1977 70 HP

Let's start with what is your WOT RPM now????<br />What kind of boat are we running??
 

johnjsa

Petty Officer 2nd Class
Joined
Mar 22, 2005
Messages
127
Re: Stainless Steel Prop - Johnson 1977 70 HP

I have a 15 1/2 Bomber Bassmaster 1982 model. WOT on my tach is 6000 rpm, not sure if the tach is reading correctly or not. I also have a CMC tilt/trim unit on boat.
 

willamettejeff

Chief Petty Officer
Joined
Nov 15, 2004
Messages
550
Re: Stainless Steel Prop - Johnson 1977 70 HP

Also need to know if current prop is cupped or not. I have been very happy with a 13 3/4 by 15 cupped/ventilated prop on my 1978 70hp Johnson on my 14' fiberglass runabout. Wot rpms is just over 5800, quick out of the hole and great accelleration at all speeds and trim angles. Your results may vary.
 

willamettejeff

Chief Petty Officer
Joined
Nov 15, 2004
Messages
550
Re: Stainless Steel Prop - Johnson 1977 70 HP

Just seeing your second post John. Your wot rpms tell me your running a standard uncupped propeller as I received the same results on my motor. If you go to a stainless prop that will more than likely be cupped, I believe you'll need to go down 2 sizes to maintain the same wot rpms. So a 15" instead of 17" prop.
 

johnjsa

Petty Officer 2nd Class
Joined
Mar 22, 2005
Messages
127
Re: Stainless Steel Prop - Johnson 1977 70 HP

Not sure about the current prop whether it is cupped ot not, bought the outfir used. Whose stainless prop are you using?
 

walleyehed

Admiral
Joined
Jun 29, 2003
Messages
6,767
Re: Stainless Steel Prop - Johnson 1977 70 HP

I doubt it's un-cupped...not too many of those around anymore.<br />Let's get a part number off that prop and we'll go from there...even if it is uncupped, we still want a 17 cupped, BUT before we do that, where is the the engine mounted on the transom?? as in what holes are being used, ie, all the way down or is it lifted up some????
 

willamettejeff

Chief Petty Officer
Joined
Nov 15, 2004
Messages
550
Re: Stainless Steel Prop - Johnson 1977 70 HP

Actually Kenny, the prop that was on my motor when I purchased it last year was uncupped and brand new. The guy I bought the boat from had just purchased it. I got rid of it because it ventilated like crazy in a turn even with the engine trimmed way down.<br /><br />John, I run both Turningpoint Express stainless and Turningpoint Hustler aluminum props. Both come with a lot of technology for the price, IMHO anyway. You can of course get a higher performance prop, but you'll pay dearly for only a small improvement.<br /><br />Kenny has a lot of experience and will no doubt have some excellent suggestions and advice for you.
 

JB

Honorary Moderator Emeritus
Joined
Mar 25, 2001
Messages
45,907
Re: Stainless Steel Prop - Johnson 1977 70 HP

Moving to the new Props forum.
 
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