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Author Topic:   90 hp Mercury 2 stroke prop
sumnerdav posted 10-27-2003 10:50 AM ET (US)   Profile for sumnerdav   Send Email to sumnerdav  
On another thread, the discussion of which SS prop would be the best performing on a non-classic 17 Montack has been ongoing and several have suggested starting this thread so that some one who has replaced the stock aluminum with a SS could discuss their experience.

I'm trying to determine which SS would give me good pulling power and increased top end.


Barney posted 10-27-2003 10:58 AM ET (US)     Profile for Barney  Send Email to Barney     
Just so people will know I posted on the other thread:

"Searched the site and could only find minimal info on the 2-Stroke props for the 170. Someone mentioned a 19 stainless, but that's it. We need some data dudes." Jim

MantyMonty posted 10-27-2003 01:27 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
I just talked to Gene at Twin Cities Marine and he asked me what pitch I have on my 2004 90 2 stroker Saltwater Series Mercury at this time. I gave him the number 48 77348A45 21P. He then told me I have a 21 pitch prop in aluminum. I asked him what I should use in Stainless and he told me I should definitely use a 20 pitch SS. Probably a Trophy type. He stated the pitch tells us that with one rev of the 21 pitch prop it will travel 21 inches. He told me the top end will increase. He also said that my hole shot will improve greatly. I have one on order. I think the aluminum one I have will make a great spare.
lhg posted 10-27-2003 01:57 PM ET (US)     Profile for lhg    
I would be leery of 4-bladed Trophy Plus prop on a 170. My preference would be a Laser II. I recommend that you go to and work your way into the propeller sections, where there are descriptions of proper applications for a given prop design. From what I can tell, the Trophy is designed for bass and flats boats, and fairly high elevated running heights. They take a big bite on the water. The Laser II is shown for offshore single powered center consoles, and only needs to be run in the 3rd set of mounting holes. You may need to lift your engine up a little for this prop, but I would agree the 20" pitch sounds right if you are turning the 21 aluminum up to 5300 or so.

I run Laser II props on both of my Outrages and can vouch for them. They are excellent, and have been in the Mercury line for a long time.

MantyMonty posted 10-27-2003 04:08 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
Just left the Marine store again, and the name of the prop by Merc is the Vengance. It is a 3 blade , right hand, polished stainless, 20 pitch x 13 1/4 diameter. It comes with a new nut, washer torque sleeve and goes for close to 495.00. The motor would not be required to be moved for this prop. per the marine tech. Thats my latest news on this subject.
Barney posted 10-27-2003 04:19 PM ET (US)     Profile for Barney  Send Email to Barney     
Manty, when you get the prop for your 2 Stroke can you get some performance numbers. This is the 4-Stroke:

Rodger posted 09-11-2003 12:45 PM ET (US)
I have recorded the following performance numbers using GPS and optimal trim in calm water. 2003 MT170 with 90HP 4-stroke running 18P SS Vengence prop.
4.0 1000
5.5 1500
7.0 2000
9.0 2500
16.0 3000
22.5 3500
26.5 4000
30.0 4500
34.5 5000
39.0 5500
42.0 6000

3500 to 4000 RPM seems to be best for long distance cruising.

We'll put them in a post for "170 Montauk 90 2-Stroke performance".
Thanks Jim

MantyMonty posted 10-27-2003 04:44 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
I certainly will but not till next spring unfortunately. This 45 degree temp here in Manitowoc Wisconsin is depressing. And it's not even cold out yet! But yes I will. I am going to get the Vengance due to it being a strong recommendation from the technician at the dealership and not having to move the mounting bolts.
lhg posted 10-27-2003 05:46 PM ET (US)     Profile for lhg    
Manty - If Mercury's website is correct, you have been given bad information by someone. I suspected that was the case, so I checked, and for the mid-sized 4 1/4" gearcase, Mercury does not offer a Vengeance prop in 20" pitch. The highest available is 18". When you get above that, in SS, you need the better performance of a Laser II, Trophy Plus 4 blade, or High Five 5 blade.

See, and click on Parts Express, following links to prop selections. For anybody interested in what Mercury offers in props, for most engine brands, this is a great resource.

A great place to buy one is Easy people to deal with. A mid-sized HP Laser II prop is about $400.

CHRISWEIGHT posted 10-27-2003 06:02 PM ET (US)     Profile for CHRISWEIGHT  Send Email to CHRISWEIGHT     

is that a hewlett packard lazer?


seriously though I run a laser 2 22pitch on a 90 classic mercury and we get 42 mph at 5100, (little low) probably a 20 pitch is in the right ball park.

lhg posted 10-27-2003 06:10 PM ET (US)     Profile for lhg    
That "HP" was supposed to mean "Horsepower". I guess JimH is correct about not using initials! But buy those HP laser printers so their stock will go up.
Barney posted 10-27-2003 07:59 PM ET (US)     Profile for Barney  Send Email to Barney     
Manty, whatever prop you wind up with, thanks. Maybe sumnerdav could do some winter testing. Jim
MantyMonty posted 10-27-2003 09:52 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
After doing some internet work, it appears the prop they meant to say was indeed the LaserII. The part number48-16990A46 is a LaserII 13 1/4 x 20 pitch. I will have to give the tech another call tomorrow. Thanks lhg for the insight to this mix-up.
sumnerdav posted 10-28-2003 07:50 AM ET (US)     Profile for sumnerdav  Send Email to sumnerdav     
The Lazer II is the one that the search engine picked on the BW site, when I searched. It gave me a 24 pitch selection. I'm going to contact the dealer for a tech recommendation.

When I have whatever SS installed, I plan to do testing all winter!

fitn217 posted 10-28-2003 08:39 AM ET (US)     Profile for fitn217  Send Email to fitn217     
DO NOT....I REPEAT DO NOT buy a Trophy Plus prop for the Montauk 170. I bought a used one after a mercury dealer recommended it and put it on. The prop is so big and heavy that when in gear at idle speed the motor shakes and clangs, yes clangs like the driveshaft is banging around, and it had less of a bite on the water at slow speeds. I went to the Mercury dealer and asked them about it and the same guy told me it was too heavy for the 90 two stroke. He said it was fine to run and would smooth out at higher speeds, but that much vibration scares me. I bought the 4 blade prop because the aluminum 3 blade blows out on me every so often and I wanted to prevent that and I wanted lower planing speeds. I've never run a four bladed prop before and I don't think I ever will before. I'm going with the laser II in 20" pitch.
The dealer thinks the prop will run better with the 115 or 135 4 cylinders. I"m going to try and sell it ASAP.
fitn217 posted 10-28-2003 08:40 AM ET (US)     Profile for fitn217  Send Email to fitn217     
Make that I've never run a four bladed prop before an I don't think I ever will AGAIN!!
Barney posted 10-28-2003 12:32 PM ET (US)     Profile for Barney  Send Email to Barney     
Test away sumnerdav and have fun. We wait patiently for the results of your runs. Jim
lhg posted 10-28-2003 02:36 PM ET (US)     Profile for lhg    
I believe a 24" Laser II is WAY too much pitch for a 2-stroke 90 on a new 170 Montauk. That prop is rated for about 52 mph on the 90, and I can't believe you get that kind of speed out it.

A 20" pitch sounds about right, top speed potential around 45.

MantyMonty posted 10-28-2003 03:54 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
I talked to a Mercury Outboard factory tech today and he confirmed my choice as I listed earlier, as being the correct prop to go with the 2004 90 Saltwater Series. This being the Laser II 13 1/4 x 20 pitch. Mercury Part number 48-16990A46. I also confirmed with him that no change in engine mount holes would have to be made.
jimh posted 10-28-2003 09:27 PM ET (US)     Profile for jimh  Send Email to jimh     
It is interesting to note that when all is said and done, all the outboard motor guru's at the dealership and the factory have been consulted, and some first-hand experience is thrown in, that the outcome is just as LHG recommend in the earlier portion of the thread:

"I would be leery of 4-bladed Trophy Plus prop on a 170. My preference would be a Laser II."

"I would agree the 20" pitch sounds right."

A tip of the hat to LHG and his propeller recommendation.

Barney posted 10-28-2003 09:45 PM ET (US)     Profile for Barney  Send Email to Barney     
jimh, I agree with you. lhg has pin pointed it. I thank him for taking the time to look at it. How many people do that these days?

As for the 170 Montauk, no doubt the 2-stroke will be a performer with that 20 pitch SS prop. What interests me also is that we have 90 HP 4-stroke performance info on the Forum and no 90 HP 2-Stroke performance info yet. It will be interesting to stack these up against Tabasco's 115 EFI 4-Stroke and the new 90 HP OPTI when it appears on the Montauk. The information on all four together in one place will be good for reference, if we can get it. Whaler probably has this but it ain't available. Jim

InHerNet posted 10-29-2003 08:20 AM ET (US)     Profile for InHerNet  Send Email to InHerNet     
I have the 170 with the 90 2 stroke and changed to the Laser II 20 pitch two weeks after my purchase. The hole shot is quick and the top speed is between 42 and 43 on the GPS, with two adults aboard and a pate 27-gallon over half full.
Maybe on a good day and with only one person it would reach 44 not sure.
Barney posted 10-29-2003 07:49 PM ET (US)     Profile for Barney  Send Email to Barney     
InHerNet, Do you have some performance information like Roger put together that I reference. Even if it was the 2500 RPM and up would be good. jim
InHerNet posted 10-29-2003 09:19 PM ET (US)     Profile for InHerNet  Send Email to InHerNet     
If I get out on the water this weekend, I will record some performance numbers and post them for you.
Barney posted 10-29-2003 09:26 PM ET (US)     Profile for Barney  Send Email to Barney     
Thank You, Jim
MantyMonty posted 10-30-2003 01:12 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
I just ordered my Laser II prop part number 48-16990A46. It is a 13 1/4 x 20 Pitch for my '04 90 Mercury Saltwater Series 2 stroker from Mark's Marine in GA for 399.00 plus 4 dollars shipping/ no tax. I will have it tomorrow. The price locally is 491.00 plus tax. Thanks again for the tip lhg.
lhg posted 10-30-2003 01:52 PM ET (US)     Profile for lhg    
Glad to help out here. Let us know your results, and thanks for giving us another Mercury prop source. But how do we reach them?
MantyMonty posted 10-30-2003 02:06 PM ET (US)     Profile for MantyMonty  Send Email to MantyMonty     
Sorry, I was going to add that but I sort of forgot. The phone number is 706-782-5565. Their e-mail is .

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