Prop for new Lowe w 115HP Merc.

newt5005

Seaman
Joined
Nov 15, 2004
Messages
51
Hi- I'm looking to get more speed out of the Dealer supplied prop. Let's start with the particulars.
I have a 2014 Lowe 175 FM with a 1732 cc. 115hp, 4 stroke outboard. The gear ration is listed at 2.33. Weight, I'm guessing between 2500 and 3000 lbs based on listed hull weight plus 26 gal fuel, 2 full sized adults, engine weight, cooler and misc gear.
Current prop is a Paranah (comp) 14x13p.
Holeshot is almost instant, basically the length of the boat or a little more. If you hold the throttle at 4,000 rpm's, the nose will continue to rise until it falls off plane. At 4,500 rpm's, speed (speedometer) is at 20 MPH. The engine never feels or sounds like it's really working hard.
The engine is new, so I didn't hold the rpm's over 45 hundred for very long. I guess another question is am I not running it (the motor) fast enough? Specs call break-in between 4,000 and 5,400. Full throttle at 5,800 and 6,400. Yes, it's that new. I'm not getting a lot of advise from the dealer, just to check the Prop Selector on the Merc website.
Please also advise if I should wait until after break in period before worrying about changing props or should do it sooner than later.

Thanks.
mike
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Now isn't the time to evaluate your setup. Have to wait for full breakin.
I can tell you the 13 isn't even close to right.Maybe they gave you that so to be sure you don't lug the motor during break-in.
Just guessing based on your boat probably a 17 or 19 inch.
That 13" probably can't give us any meaningful numbers.A 17 will be closer.
 

newt5005

Seaman
Joined
Nov 15, 2004
Messages
51
Thanks for the reply. Kinda thought that might be the case. As for the reason behind the 13 pitch prop, I'm leaning more towards lack of knowledge than a protective measure on the part of the dealer. Thanks again. I'll repost after break in if I still feel the same way about the prop. mike.
 

SkiDad

Lieutenant Commander
Joined
Jul 18, 2010
Messages
1,518
you definitely do not want to run that prop - I would start out with a 19 pitch and that should get you around 40 mph. Maybe a 17 if you are REALLY heavy.

i think you might be able to pick up different snap in blades for the paranah - but I don't think they are as fast as an Aluminum prop - just what i've heard.
 

jestor68

Commander
Joined
Jun 12, 2012
Messages
2,308
The Mercury prop selector comes up with a 19 pitch and says 5500 rpm @ 34 mph with a calculated weight of 3014 lbs.

That means you want a 17 pitch Black Max(or Solas) to get you closer to 6000 rpm.

Your dealer is either kidding you or he's completely wacko for putting a 13 pitch plastic prop on there.

Unless this a pontoon boat.

Since it's a new boat, he must put the correct prop on it and test with you to see that it's right.

The Mercury engine tests of the 115 on boats like your's ran 17 and 19 pitch props at 5900 and 5750 rpm respectively. The 17 was a Spitfire and the 19 was a Laser II. The 17 Laser II would have been better.

Does you 115 have the "command thrust" (V-6) lower unit? The gear ratio sounds like it, as the regular gear ratio is 2.07.
 
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