Propeller setup help!!

[Jackie]

Hey guys,

 

 

just found a pretty good deal on a 3 blade 21p laser 2 ss prop. The Model #is 48-16546 A40 21p diameter 13 7/8. The seller said it came off a 135hp Merc. Just wondering if that will fit my 2004 Mercury Optimax 115hp 2 stroke on a 16ft Ranger R61 and 5.5inch jackplate. I am currently using a 3 blade 22p laser 2 ss prop, getting 45mph, 5000RPM WOT with one person, half tank of gas, light load. The jackplate is set to 2.5 below pad, and water pressure gauge (analog gauge) at WOT indicates a little over 10psi, and sometime drops a little below 10psi...even when I trim down a bit at high speed the pressure gauge still wouldn't go up...wondering if that's fine since it's an analog gauge, maybe not 100% accurate...and I can't get it to go over 5100 rpm...so thought maybe I should try a 21p prop and maybe that will increase the rpm and hopefully some speed as well...

please give me some advise!!

 

Thanks a bunch!

 

Jackie

[DRIFTER_016]

What's the diameter of the prop you are currently using?

If it's the same as the one you are looking to purchase you should gain 200 rpm with it.

What is the max rpm of your motor? That will help you decide whether it's worth it or if you should drop more pitch or even go to a 4 or 5 bladed prop. It would be an idea to talk to your local dealer or if you know all of the pertinent info regarding your boat use the Mercury Prop Selector tool.

[Jackie]

What's the diameter of the prop you are currently using?

If it's the same as the one you are looking to purchase you should gain 200 rpm with it.

What is the max rpm of your motor? That will help you decide whether it's worth it or if you should drop more pitch or even go to a 4 or 5 bladed prop. It would be an idea to talk to your local dealer or if you know all of the pertinent info regarding your boat use the Mercury Prop Selector tool.

 

 

 

The diameter of the prop I am using right now is 13-1/2. The max rpm rated for my motor I believe is 5500. The Prop selector site is very useful! I punched in all the info and it recommend me to get the Laser II Features SS 3 blade 13.25 diameter 21p 899006A46...that's exactly what I am having in mine.

Thanks for the site! Helped a lot!

[Terry]

I think you are going the wrong way... I think you want a 21 or 22 pitch but smaller diameter...say 12 3/4... 22 high five prop

push less water with more forward movement

[SlowPoke]

I think you are going the wrong way... I think you want a 21 or 22 pitch but smaller diameter...say 12 3/4... 22 high five prop

push less water with more forward movement

Agree. Or keep diameter the same and drop to 19 or 20 pitch... availability will probably dictate what size you end up with

[hirk]

Does it come with a hub kit or is it a rubber hub?If its rubber it may not fit because it may be intended for a larger diameter prop shaft. If its a hub kit you may just need to buy another hub to fit your engine. Your psi should be 15minimum at wot an less at lower rpm. Are you still throwing a rooster when your running wot and trimmed out? Did your rpm/speed go up after you raised it too 2 1/2" without having to over trim and get alot of prop slip? This is just a guess but you either have an engine issue at high rpm (doubt it) or you need more bow lift, like I mentioned before you are not running a very good prop for that,look for a tempest or a raker(with a hub kit). If the 21 fits try an test it 1st,it may run better for you than what you have but you will still be leaving a few mph on the table (not getting the max out of your boat).

[HTHM]

I agree with Hirk, (heck he is VERY knowledgeable on these matters), your water pressure seems a bit low. I run a 2004 opti as well, 150 hp, and all the research that I have done indicated that 3 1/2" below the pad is the sweet spot for most Rangers.

You may want to check this page out: http://www.kencook.net/Setupart.html or look at other Bass Boat boards as well, BBC comes to mind as a good resource.

Good luck getting her dialed in!

[Jackie]

Does it come with a hub kit or is it a rubber hub?If its rubber it may not fit because it may be intended for a larger diameter prop shaft. If its a hub kit you may just need to buy another hub to fit your engine. Your psi should be 15minimum at wot an less at lower rpm. Are you still throwing a rooster when your running wot and trimmed out? Did your rpm/speed go up after you raised it too 2 1/2" without having to over trim and get alot of prop slip? This is just a guess but you either have an engine issue at high rpm (doubt it) or you need more bow lift, like I mentioned before you are not running a very good prop for that,look for a tempest or a raker(with a hub kit). If the 21 fits try an test it 1st,it may run better for you than what you have but you will still be leaving a few mph on the table (not getting the max out of your boat).

 

 

yes it comes with a hub kit. and yea I am still throwing a rooster while running WOT and trimmed out, so I have to trim a bit down to avoid that. My rpm and speed did go up after I raised the jackplate to 2 1/2, I didn't have to over trim and there is not a lot of slip.

Thanks for the advise!

 

Jackie

[Jackie]

I agree with Hirk, (heck he is VERY knowledgeable on these matters), your water pressure seems a bit low. I run a 2004 opti as well, 150 hp, and all the research that I have done indicated that 3 1/2" below the pad is the sweet spot for most Rangers.

You may want to check this page out: http://www.kencook.net/Setupart.html or look at other Bass Boat boards as well, BBC comes to mind as a good resource.

Good luck getting her dialed in!

 

But I tried 3" below pad before, i only got 35-40mph and maxed out on 4500rpm wot and had to lower the rpm to gain speed at some point. and the rooster tail was as high as the CN tower...So after I raised the plate, I gained about 10mph and maxed out at about 5100 rpm wot, roostertail just levels with the top of motor cover...But the problem is the psi seems a bit too low...it's weird tho, because the first time I tried after raising the plate the psi was around 12-13...but then after a couple run the psi drops to 10 and stays around 9-11psi...the reading is not constant somehow.

[Jackie]

I think you are going the wrong way... I think you want a 21 or 22 pitch but smaller diameter...say 12 3/4... 22 high five prop

push less water with more forward movement

 

Do they even make 12 3/4 in 22 pitch 3 blade? Thought they only have 12 3/4 in24p 5 blade for my motor...

[Terry]

I am not sure of the diameter you can put on that engine but , I do think you need to go smaller

there is a reason why you are not reaching full rpm

 

and you are not getting the boat out of the water enough by the sounds of it, not enough front lift like I said in the other thread..

the only water the boat should be touching is at the very back of the boat...

I have owned 10 bass boats and did tourneys for 12 years, so I am just stating what I learned over the years through trial and error

 

I would call up Paul at Top Gun Marina outside of Bradford 905-775-0862 and ask him. tell him you want to buy a better used prop for it, he has always let me try props till I get it right

[Jackie]

Yea for sure there is not enough front lift because I had my brother stay on shore watching me drive the boat, and he said the bow didn't lift up much...but then i saw some videos on YouTube, most of the rangers don't get much bow lift except the Z series... Wondering if that's how it is for the R61... But yea I will definitely try some smaller props and see if theres big deference in between. I'll call Paul and see if he has any 21p or 20p props that will fit the 115 and let me try it for couple days.

Again thanks for the help Terry! Hope I can get it up to 50-55mph soon!

[misfish]

Wish I had my old pics/vids. Mine got up, and was gone with the high 5 that Terry mentioned.

[linweir]

I used to own an old model 115 HP Merc. Prop should be about 12.5 ~ 13 diameter, and 19~ 23 P.

Don't use over 23 P prop.

Higher pitch, lower RPM.

[DRIFTER_016]

I run a 13X19 on my 1991 90 horse Merc and it revs to about 5,300 with no jack plate.

It tops out at about 36 mph with a 3 blade aluminum.

 

This is the boat.

 

[misfish]

run a 13X19 on my 1991 90 horse Merc and it revs to about 5,300 with no jack plate.

It tops out at about 36 mph with a 3 blade aluminum.

 

 

 

Some of us,dont have all day to get to THE spot.

Edited April 29, 2012 by Misfish

[Terry]

My Sylvan with a 1990 merc 90hp get 42mph(GPS) with a high five

with a 3 blade I got 2 more mph but the bow was way to loose

 

I've rode bucking broncs that bucked less , so the high was the way to go

[DRIFTER_016]

Some of us,dont have all day to get to THE spot.

 

I think it might go faster when I put the new 115 and jack plate on next year or the year after Mis.

[hirk]

Has the impeller been changed? If you dont know I would change it, if its on lits lasts legs that could mean an extra 5psi without touching anything else. The other lazer may give you 1-2 mph more but if you want the boat to fly try to find a tempest because the have more blade rake they will lift the bow much better than the lazer.

[Jackie]

Has the impeller been changed? If you dont know I would change it, if its on lits lasts legs that could mean an extra 5psi without touching anything else. The other lazer may give you 1-2 mph more but if you want the boat to fly try to find a tempest because the have more blade rake they will lift the bow much better than the lazer.

 

 

Not sure if the impeller has been changed or not, gotta check with the dealer...

Tempest to too expensive...and how much more am I really gonna gain by spend that much extra?

[HTHM]

Your impeller should be changed every two years at a minimum, ideally every year. As for gaining speed, the reason a boat gets dialed in is so that you are able to run at the most efficient rate possible. My Ranger can hit 57 - 58 MPH, but rarely goes over 40.