Prop Pitch

[Double Barrel]

I just got a 115 4-stroke Merc. The dealer put a 20 pitch on it. Does this sound right?Someone told me if the rpm's are between 5000-6000 that is the correct pitch? Any information on this would be helpful. Thanks!

[marine_man]

Double Barrel,

To give you a better guess as to if the 20 pitch is right you need to provide more info.. what brand & model of boat for starters...

If you've already run it provide the RPM at WOT (wide open throttle)...

I believe you are correct as far as the RPM range goes... 6000 is the max RPM recommended.. so you'll want a prop that will run you up near 6000...

Without more specifics it's difficult to give a good answer...

marine_man

[Double Barrel]

I'm sorry the motor is on A 1700 Lund Angler(around 1200 lbs.) The top speed was around 32 and I didn't notice the rpm's,but I thought I should be going faster than I was.

[Xplorer]

DB,
Not an exact match, but i have a 1160# lund prosport and a 90hp 4 stroke. At WOT I am at 39.2 mph/gps with 2 in boat and full tank.
Running a 17p prop.
I think you need to try a couple lower pitched props to see what is your best mix between hole-shot and top end. You running a stainless or aluminum prop??
You may want to look at either merc or yammy's HSOforum (i think your motor is a yammy powerhead) to see if they have any test run data for your motor. You are defintily running slow, you should be above 40mph gps WOT.
Xplorer

[lundrunner]

Hey BOA,

Are you sure that NEW boat of yours wasn't sunk over by Blue Fin Bay on Kabby? Maybe she is just full of sand and that's what is slowing you down.

[Surface Tension]

Just as what was mentioned earlier, you'll have to find out your RPMs at WOT before giving any consideration to another prop.

[Crestliner-fever]

I've got a 1750 Fishhawk with a 115 yamaha 4-stroke, I'm running a 19 pitch & i can run it out around 47-48 mph on the gps, that's running 6000 rpm. ( that's on Allumnium prop )

Put the Throttle down & let it run!!!

[trollingforeyes]

Hey Crestliner: What will it do if you really open her up??

[musky hunter]

That pitch sounds a bit high to me. If you only get 32 mph out of it, you're rpm may only be about 4000 rpm. I would think you have a 40 mph boat. (Speedometers are inaccurate, use a gps for a true speed indication). I'd try a 17 or even a 15 pitch. Go see you're dealer or local prop shop. Sometimes they'll even let you try a used prop for free and then you would know for sure.

[GoodToGo]

I have a 115 merc 2 stroke on a 19' Starcraft Superfisherman. It came with a 21" pitch prop. It ran about 42 mph at 4900 rpm. After hitting a log I switched to a 19" 4 bladed composite. I kept my top end but added more snap coming out of the hole. It increased rpm's to 5200, the top end of the recommended range. Sounds like you could use less pitch, you should be able get 40 mph.

[marine_man]

Double Barrel,

Do get the best results (that you are happy with at least), the best bet is to find out what you're turning for RPM at WOT... then we'll have a better feel for what to recommend. Otherwise it'd be a guess..

marine_man

[This message has been edited by marine_man (edited 03-25-2004).]

[Double Barrel]

Found out yesterday that I can get 5300 rpm at WOT. Think I need to go to a 18 pitch.

[marine_man]

Double Barrel,

for some reason it seems that most dealers stock odd numbered size props... based on your RPM I'd say that I would go for a 17 pitch prop... but to be sure... how many people were in the boat when you ran it last, did you have a full tank of gas & a full load of equipment?

marine_man

[Surface Tension]

You found out you can or, you are running 5300 RPMs?

[Double Barrel]

It will run 5300 rpm's at WOT. I was in the boat alone with 1/4 tank of gas.

[Guest]

Hey double barrel. What did you end up with for a prop and your rpm at WOT? The reason I'm asking is that I just bought the same boat, Angler 1700 SS, with the same motor, Merc 115 4 stroke, and it will be prop-ed out this week. I'd appreciate knowing how your search for the right prop came out.
Thanks
Randy

[Double Barrel]

Randy,finally I ended up with a 18 pitch prop. RPM's at WOT were 5900. I thought new boats were ready to go,but on my occasion it took around 5 weeks to get the steering wheel so it doesn't come out,depth finder so it doesn't freeze up(had to send it back,they said 100 went out with glitches go figure (lol) and the correct pitch prop to the desired rpm's. What a nightmare !
Like my buddy says there are two happy days of a boat owners life, the day he brings it home and the day he sells it !!