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Author Topic:   170 MONTAUK: Best engine for 2005
scubamoe posted 12-08-2007 12:19 AM ET (US)   Profile for scubamoe   Send Email to scubamoe  
I have a 2005 170 MONTAUK with a 90-HP two-stroke. I have seen a few with Yamaha 100-HP and a lot of the same model with the Mercury 90-HP four-stroke. What is the ideal fishing engine, speed engine, sound engine for this boat for someone who isn't worried about the maximum engine rating, within reason. Is it the 115 OptiMax? Yamaha? E-TEC? Also not very worried about fuel consumption.

Answers from experienced owners and operators would be valuable to me.



bigjohn1 posted 12-08-2007 10:14 AM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
I own [a Boston Whaler 170 MONTAUK] powered by a Mercury 115 EFI four-stroke. Back in 2004 when I bought the boat, I intentionally overpowered the boat with this model as it was the only outboard equipped with EFI at the time. The 90 four-stroke at the time had carburetors and my dealer was not willing to bring in a 90 OptiMax. The engine runs great and the boat has plenty of power but prop choices for this engine are more limited as it runs a higher gear than the 90 4-stroke.

The current model of Mercury 90 4-stroke is equipped with EFI so that engine should be on your short list along with the 90 E-TEC. As a personal aside, I hate the shape and looks of the current 90 and 115 Mercury's. Something about the weird shape of that cowl on a small Whaler.

sosmerc posted 12-08-2007 12:13 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
I have a number of customers with older Montauks that chose to go with the Optimax 90 and Optimax 115 and they have been very pleased with the performance and economy. No problems to speak of. If I had a Montauk for myself, I would go with the Optimax 115 "without hesitation". (pun intended)
Mambo Minnow posted 12-08-2007 03:02 PM ET (US)     Profile for Mambo Minnow  Send Email to Mambo Minnow     
I have ridden this fall on a friend's new Montauk 170 with the L4NA Fourstroke 90 EFI. It's a beautiful engine...quiet, powerful and trimmed well on the stern. It's overbuilt...basically a detuned Verado w/o the supercharger.

Another engine I would take a look at is the brand new Honda 90 fourstroke. Redesigned this year with EFI and has "BLAST" to boost low end torque.

jimh posted 12-09-2007 12:31 AM ET (US)     Profile for jimh  Send Email to jimh     
For the engine with optimum sound I would not recommend the OptiMax. It generally tests out as the loudest of the modern engines. The quietest engines are often the four-stroke engines, although the E-TEC is not much louder at idle speed. At full-throttle speeds most of the modern engines are fairly close in their noise signature.

For the engine for optimum fishing, I would not get the new Mercury Veradito 90-HP. Its cowling is too tall. The E-TEC has a lower profile. This might be important in fishing for working lines over the engine.

For speed, the more horsepower with less weight the better. Among the 115-HP motors look for best power to weight ratio.

sosmerc posted 12-09-2007 01:31 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
According to Boston Whaler's posted data comparing a 115 Optimax noise level to a 115 Merc FourStroke noise level:
They produce exactly the same dB(A) at wide open throttle (101) and exactly the same (91) at 3000 RPM. @1000 rpm they are within 1 dB(A) of each other. @600 rpm the Optimax is noisier (66) compared to (59) for the FourStroke. I would call this pretty even as far as noise level goes.
sosmerc posted 12-09-2007 05:34 PM ET (US)     Profile for sosmerc  Send Email to sosmerc     
Some more interesting data (from Boston Whaler data)
A 150hp Optimax @5550 RPM 96 dB(A)
A 150 Verado @ 6400 RPM 98 dB(A)
Not too shabby for the old Optimax that gets a bad rap for being too noisey. (granted, it clearly is noisier at lower rpm, but perhaps the GenII's will show improvement in that range as well) The Optimax 150 in the comparison I cited was tested in 2004 and the Verado in neither is a "Gen II" engine.
scubamoe posted 12-09-2007 05:57 PM ET (US)     Profile for scubamoe  Send Email to scubamoe     
Thanks for the replies. I have done a bit of searching on this web site and others and have a lot of info to work with. I worked for a Brunswick boat company for years and have my own bias for non black I/Os. I am more open to black engines cowlings, but currently have 4 yamahas in my garage, the largest an F150.

The current engine performs well but the noise, smoky start ups, mechanical noises it makes coming down from high RPM and blue oil it leaves in the slop well is making the family look at four strokes.

Now its a matter of firing up excel and optimizing the data.

Thanks again,


Feejer posted 12-10-2007 07:28 AM ET (US)     Profile for Feejer  Send Email to Feejer     
You just gotta love that F150. I had that on my Sea Hunt. Great engine except the clunky shifting
jimh posted 12-16-2007 09:20 PM ET (US)     Profile for jimh  Send Email to jimh     
I was hoping that Boston Whaler would have some test data for the new "Globe Graphics" OptiMax motors. (The presence of the Globe graphic on the cowling seems to be the best indicator of a newer OptiMax that has the improvements generally referred to as GEN-II.) But just about the time when the new OptiMax motors became available, Boston Whaler stopped selling their boats with the Optimax motors, This is unfortunate because I have a great deal of faith in the test data that Boston Whaler publishes, and I was hoping that they'd have some reports of a Globe-Graphic OptiMax on the same model as the older OptiMax was tested. By comparing the data, we could get an idea of just how much difference there was between the old and new motor's sound signature.

I really haven't seen any test data which includes sound level information for the new Globe-Graphics OptiMax motors. Even when some test data shows up, it will be a bit tricky to compare it to the old motors.

As for the cowling height and its effect on fishing, the Mercury four-stroke motors are not unique in being rather large. Most of the other brand four-stroke motors are fairly big when compared to a good old fashioned two-stroke like a Yamaha 90-HP.

If you need a motor for trolling, Mercury offers a feature when you have the optional SmartCraft system which can set and maintain the motor at slow speeds for trolling. I don't have all the details of this, but give it a look. It is a nice feature on the motors that support it. It may only be applicable to motors with Digital Throttle and Shift.

glen e posted 12-16-2007 10:10 PM ET (US)     Profile for glen e  Send Email to glen e     
Jim - once again I can't come up with exact data but I also have been looking for some comparison between old and new globe opti's ...Having been on a 225 26 foot with 04 opti's and then the same boat with new globe motors, I can't tell a damn bit of diff...if I listen real cloesly they sound a bit quieter but not enuf to proclaim it an "improvment", IMO

and troll control - low speed opertion by smartcraft - is on all merc opti and verado products..... and new gen verados and opti's with DTS have both "troll control" and "cruise control" - which means digital settings at all rpms...i.e if you are at 4000 and want to go to 4250, it's just one button to push....

itl posted 12-20-2007 06:54 AM ET (US)     Profile for itl  Send Email to itl     
I used to own 115 Merc Optimax, 2004 model. What comes to motor noise level, I think it is not bad at all. Yes, it is noisier than 115hv four strokes (compared to Yamaha and Suzuki), but the sound of Mercury is quite nice and would say that noise level of the Optimax is something what you should not consider if you are considering Optimax to your boat. Maybe those "old" Optis are even noisier than new ones. Have not heard new Optis yet.

What comes to these desibel readings. I woould say the noise level measured by desibels is next to useless, because desibel readings only tell what is the pressure level of the noise. It does not tell how the noise actually sounds. For example, we could have two engines, other one makes 57db and other makes 60db noise level at idle. It is possible that 60db engine sounds more comfortable even it is a bit louder, because nature of the sound is comfortable.

Ok, this is a bit difficult to explain, I give you another example. If you hear two noises, both are 80db level. Other noise is a nasty grinding sound and the other one is nice classic music. Which one you prefer to hear all day long?

In general, 4 stroke engines sounds more comfortable than two strokes, because exhaust valves in 4 stroke "breaks" the sound wave which is coming out of the cylinder and 4 strokes also have less power strokes than 2 stroke, if the number of cylinders is the same. 4 strokes just make less noise by nature and for some reason the sound of the 4 stroke at idle is more comfortable than sound of two stroke.

Anyway, if buy 4 stroke or 2 stroke dfi, I dont think you get a bad engine, no matter what brand you choose. All modern engines are pretty good, but a charasterics of the engines (4/2 stroke) are a bit different.

boatdryver posted 12-20-2007 10:29 AM ET (US)     Profile for boatdryver  Send Email to boatdryver     
Itl, all of us non-engineer types should thank you for that easily understood explanation of decibel levels and what they do and do not reveal.

If you are in Finland now, how many hours of daylight do you have as we approach December 21?


Mambo Minnow posted 12-20-2007 12:34 PM ET (US)     Profile for Mambo Minnow  Send Email to Mambo Minnow     
I have no scientific data, but I do have first hand report from my Mercury service shop that my first generation Opti's are much noisier than later models.

I was told there is a silencer added to the exhaust system. If SOSMERC or someone else sees this on the Gen 2's, please post pictures of the differences. Surely, some "globe" motors will be coming in soon for 100 hour service in warmer climes.

glen e posted 12-20-2007 03:19 PM ET (US)     Profile for glen e  Send Email to glen e     
I can't tell a damn bitt of diff in the globe motors vs the year before - been on lots of em....
boatdryver posted 12-20-2007 04:27 PM ET (US)     Profile for boatdryver  Send Email to boatdryver     
Glen, do you know for sure why Mercury made those changes in the rod bearings in the newer versions of the Verados? I saw this in a video produced by Mercury, in which a large gentleman heading up the verado line showed closeups of the old and new versions.

Was it just to increase high rpm efficiency/Horsepower or was it to correct an anticipated longevity problem?

It seems unusual for them to do that in year 3 of a new product and turn it to a positive for marketing purposes.


itl posted 12-21-2007 07:53 AM ET (US)     Profile for itl  Send Email to itl     
Yes, I am in Finland at the moment. It is pretty dark here, we got daylight from 9:00 am to 3:00 pm :(

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