70HP Johnnyrudes - Prop survey

CBGale2

Lieutenant Junior Grade
Joined
Apr 22, 2009
Messages
1,026
Pretty sure there's a handful of you guys running 70's on your tin. The prop on my motor I just picked up has seen better days. Looking for opinions, the whole prop selection thing makes my head hurt. Lol.
 

laurentide

Lieutenant Commander
Joined
Jul 24, 2011
Messages
1,869
13.25 x 17 on mine. Good hole shot and 5600 WOT on my 18'er. I get low 30's with a cabin and canvas enclosure with just me on board.

I think this is probably the most common size/pitch for these engines. I love the engine, it's very reliable and "OK" on gas.
 

CBGale2

Lieutenant Junior Grade
Joined
Apr 22, 2009
Messages
1,026
Cool, got one in the parts pile I scavenged out of my last project. Not in perfect shape, but I'll give it a go!
 

Watermann

Starmada Splash of the Year 2014
Joined
Jan 12, 2013
Messages
13,747
One thing to be aware of if you go shopping for a new prop. They are way different than the old ones as far as cupping and a more aggressive rake design. In other words if you run say a 17p old style that has no cupping and buy a 17p new style prop it will eat a couple hundred RPMs at the same pitch.

I'll be doing the same dance on the 140 Merc I'm working on as it has a 17p prop on it right now which looks to be the original that came on a way heavy old timey 70's glasser. The key is to have to have a working tach or a great ear to tell if you're at the right RPM.
 
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