Picking a prop for Mercury 115 Tower of Power

mpl006

Cadet
Joined
Feb 23, 2013
Messages
19
I have a 1986-87 115 that is still kind of flaky. I finally got it running ok and went out today to go fishing and hit something or maybe the prop just decided to crack because I didn't see anything on my graph but that's neither here nor there. I am planning on getting a direct replacement of the aluminum prop that was on the boat because I am not 100% sure that the reason I am not hitting correct WOT RPMs is because of the prop or the engine still not running correctly. So after I get it in and get the engine working better, I am planning on getting a SS prop to have as my main prop and have the Al one as a backup. Right now I am looking at the Mercury Laser II, the Mercury Vengeance and the Stiletto Advantage props. The Al prop is a 23P and the biggest Solas Saturn prop that I found on the site I am looking at is a 21P which maybe fine but until I find out from getting the engine running better, I don't know but let's put that one as a maybe.

What I am planning on doing with the boat. Most of the time I will be fishing and so just running from spot to spot but also plan on doing some tubing with it in the future. This is my first boat and am not really in need of something that can get me going at exuberant speeds.

What I know about props. Next to nothing. I understand the theory behind pitch and changing to adjust the WOT RPM but past that, when it comes to this brand and that model, I am lost. If I have missed a good brand/model, let me know what to look at. I know I probably just opened a can of worms, so hopefully it stays civil. That is something I have been very impressed with iboats so far is how the members conduct themselves compared to other forums I frequent.
 

Georgesalmon

Lieutenant Commander
Joined
Apr 14, 2012
Messages
1,793
Re: Picking a prop for Mercury 115 Tower of Power

Can we get some info about your current WOT rpm and boat weight, speed, etc. Even though the engine isn't quite up to par those current numbers would help. The pitches you are looking at are for very light fast boats, not your typical loaded down fishing rig.
 

mpl006

Cadet
Joined
Feb 23, 2013
Messages
19
Re: Picking a prop for Mercury 115 Tower of Power

It is a 15' fiberglass boat that from what the guy that I bought it from, my wife's uncle, said it was supposed to be a pretty fast hull design. It was designed and built in Ruston, La. in 86. Not sure on the weight yet, I was going to try to weight it sometime soon just so I could know that. The last time I was out before yesterday, since it cracked pretty early in the day, I was able to get consistently 4100 RPM with the motor surging to about 4500. Not sure if that was all it had in it or if it was because it's still not quite right. I was running around 37 or so on my GPS.

Like I said, I know that I need to be in the range that Merc spec'd for the boat, but if this or that prop will get me more speed, that doesn't really mean a great deal to me.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,465
Re: Picking a prop for Mercury 115 Tower of Power

It is a 15' fiberglass boat that from what the guy that I bought it from, my wife's uncle, said it was supposed to be a pretty fast hull design. It was designed and built in Ruston, La. in 86. Not sure on the weight yet, I was going to try to weight it sometime soon just so I could know that. The last time I was out before yesterday, since it cracked pretty early in the day, I was able to get consistently 4100 RPM with the motor surging to about 4500. Not sure if that was all it had in it or if it was because it's still not quite right. I was running around 37 or so on my GPS.

Like I said, I know that I need to be in the range that Merc spec'd for the boat, but if this or that prop will get me more speed, that doesn't really mean a great deal to me.

Ayuh,.... It sounds like ya got a Serious Fuel Delivery Issue....

Get that Fixed before ya burn yer motor down....
A Lean condition induces Detonation, which will turn it into an Anchor in No time Flat...
 

mpl006

Cadet
Joined
Feb 23, 2013
Messages
19
Re: Picking a prop for Mercury 115 Tower of Power

So after a little bit or working on the fuel system, aka replacing just about everything but the tank, I got the boat running correctly today. With a 12.5" 23" pitch black max, I got the motor to between 5000 and 5100 at WOT at 41 MPH! Now back to my original question, when it comes to brand/model of stainless props, what should I be looking for?

Also, should I with a 23" or should I go to a 21"? If both would be OK, I would like the one with the better hole shot over top speed.
 

gbrowne9

Petty Officer 2nd Class
Joined
Jan 1, 2010
Messages
102
Re: Picking a prop for Mercury 115 Tower of Power

i have a 115 merc and the best prop i,ve used is a turning point hustler sold here on iboats. on my boat [ crestliner apollo 660 ] the t/p ran as fast or faster than a s/s prop.
 
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