Prop Guidance needed....

You know the drill..

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Retired OG
Posts: 97
Joined: Tue Jul 04, 2017 10:51 am

Prop Guidance needed....

#1 Post by Retired OG » Wed Apr 11, 2018 9:03 am

What I have is a 14X13 prop on my old 50 HP Evinrude and I managed to spin the hub the other day....I could never get it up to WOT and the best it would do was about 18 MPH at 4500....at 4700 rpm, it would start cutting out like it may have been starving for fuel???? I've rebuilt the carbs, replaced the fuel lines and set the timing to factory specs. What I'm wondering is if maybe the old prop was the culprit? I'm thinking maybe a 14X11 might be a better choice?

FWIW, I've also replaced the stator, rectifier, timing sensor... I also had a friend give me a spare 14X13 prop
1973 Kayot with 1972 Evinrude 50 hp Lark

crookedlaker
Posts: 184
Joined: Fri May 16, 2014 7:45 am
Location: angola IN

Re: Prop Guidance needed....

#2 Post by crookedlaker » Thu Apr 12, 2018 7:27 am

you really need to get the engine running properly before you look at props.
what is the recommended max RPM for your engine
18 mph on a older pontoon with a 50 is probably pretty close to top speed
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Retired OG
Posts: 97
Joined: Tue Jul 04, 2017 10:51 am

Re: Prop Guidance needed....

#3 Post by Retired OG » Thu Apr 12, 2018 8:18 am

A lot of the tuning at this point has to be done under power...and I'm wondering if a too large pitch could actually cause the crankcase to load up with fuel/oil, thus the intermittent cutting out....my engine revs just fine when it's not under a load.

ETA: I realize 18 mph is probably gonna be close to my top speed and I'd be happy with that...I just want to be able to do it at about 5500
1973 Kayot with 1972 Evinrude 50 hp Lark

Retired OG
Posts: 97
Joined: Tue Jul 04, 2017 10:51 am

Re: Prop Guidance needed....

#4 Post by Retired OG » Thu Apr 12, 2018 2:21 pm

Well, I just got back from the lake because I wanted to see if the prop I was given was any good...It left more questions than answers.

I was able to get it up to 5200 rpm before it would start cutting out....also the speed dropped off by about 1.5 mph with the same rpms'...it's supposed to be the same pitch and diameter, but it's been filed....how much, I don't know.....it's also an OMC as compared to the one I took off, which is a "Michigan"...right now, I'm more inclined to keep the diameter and pitch the same, keep my speed down and make it easier on both the engine and fuel consumption...
1973 Kayot with 1972 Evinrude 50 hp Lark

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