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Author Topic:   170 Montauk - Mercury 90hp Optimax
OzWhaler posted 07-27-2004 05:41 AM ET (US)   Profile for OzWhaler   Send Email to OzWhaler  
I have the choice of Mercury Saltwater 90hp 2 stroke, 90hp 4 stroke, and 90hp Optimax for my Montauk.... I am after reliability (No.1), running long distances on a plane and also slow trolling use...
Has anyone any experience with the Mercury 90hp Optimax on a Montauk ? The engine specs look good and also the weight and advertised fuel economy.... price is a little bit more - I'd appreciate some comments from experienced owners..
Clark Roberts posted 07-27-2004 07:08 AM ET (US)     Profile for Clark Roberts  Send Email to Clark Roberts     
Oz, what a delima! Here's my take on it: The 2 stroke will be the most reliable (less moving parts, easy access for maintenance...proven basic design since about 1987. Also most likely the best performer and the lightest of the three; the Opti will most likely give you the best economy and almost if not same performance as conventional 2 stroke; the 4 stroke will be best for slow speed and will also get great economy (maybe as good as opti). Now I've never owned a 90 Opti or a 90 4 stroker but have owned lots of 90 2 strokes, 115 EFI four stroker, and a 135 Opti. Above are simply my opinions... I would get the conventional 2 stroker while they are still made and try to wear it out, then trade for a current motor and by then the choices may be easier. happy Whalin'... Clark... Spruce Creek Navy
Knot at Work posted 07-27-2004 10:28 AM ET (US)     Profile for Knot at Work  Send Email to Knot at Work     
I run the 90hp 4 stroke.

Sips Gas.
No Smoke.
Hardly hear it

No added Oil to gas.

Plenty of power.

I would do it again with a 90 Hp 4 stroke

DaveH posted 07-27-2004 11:05 AM ET (US)     Profile for DaveH  Send Email to DaveH     
I would choose the 90hp 2-stroke first based on first cost, low end torque, and simplicity.

Although not part of your list, I would choose the 115Hp EFI 4-stroke second. It would require extra money up front with a dealer swap out. This engine offers the best of all arrangements for top end speed, better low end torque, economy (EFI vs carbs), and emissions.

RonB posted 07-27-2004 01:25 PM ET (US)     Profile for RonB  Send Email to RonB     
Not sure if it is comparing apples to apples but I had the 2003 90HP 2 stroke on my 2003 Montauk and I have the 2000 135 Opti on my 2000 18 Outrage. Never had a 4 stroke but would be concerned about winterizing a 4 stroke for 5 months in the Northeast. Not sure where your boatong area is.

Things I didn't like about the two stroke included the smoke, sometimes hard to start, the vibrations in the motor which created a bad shake in the bow rail around idle, and the fact that the oil fill was on the motor.

I did like the performance of the boat/motor package and the fact that she was a simple motor.

My 135 Opti has an external large oil tank (not sure how the 90 HP Opti would be rigged), gets great economy, uses less oil (although more expensive), is better for the enviroment and has plenty of power.

I have not had issues with either at troll.

If your plan is to keep the boat for a good number of years, and you have a long boating season I go with the Opti or 4 stroke. With a shorter season I'g go with the Opti.


erik selis posted 07-27-2004 02:47 PM ET (US)     Profile for erik selis  Send Email to erik selis     

If you plan on doing a lot of trolling then I think the 90-4 stroke is the better choice. I agree with DaveH about the 115Hp EFI 4-stroke. If I were to upgrade I would certainly go that direction. We're hearing a lot of positive reactions about this motor on the 170 Montauk. I am running the 90Hp 2-stroke on my 170 and it is a powerful motor. I have to say that I don't like the smoke when trolling and at times it literally makes me sick. Especially when it's hot. At trolling speeds it also consumes a great deal of fuel. I don't know about the 90Hp Optimax on the 170 Montauk but I have tried the 115Hp Optimax on the 190 Nantucket and this was a huge disappointment for me. A very sluggish combination. I'm sure though that the 90Hp Optimax will be a much better performer on the 170 Montauk. I think this would be my third choice.


Camuyano posted 07-27-2004 03:04 PM ET (US)     Profile for Camuyano  Send Email to Camuyano     
I own a 170 with the 90 4-Stroke and absolutely love it. It is clean and quiet and has plenty of power for MY needs. I use the boat for cruising with the wife and friends and fishing on the Potomac. (No tolling yet, though.) I've only had this boat for three months but I don't think that the 2-stroke is necessarily more reliable. I owned a four stroke for about four years on a sailboat and had no problems whatsoever.

In my opinion the advantages of the 2-strokes are low-end torque and cost. Also, the numbers on the Opti are very similar to the four stroke since it is a "clean" two stroke. Given your requirements of long distance cruising and low speed trolling I would seriously consider the four stroke. Like some have said many times before, the 115 four stroke EFI would probably be the ultimate 170 Montauk engine but if you're not willing to go through the trouble of doing the engine swap or live in a state where it would be illegal, the 90 four stroke is a good alternative.


OzWhaler posted 07-27-2004 09:18 PM ET (US)     Profile for OzWhaler  Send Email to OzWhaler     
Thanks for the much valued input... 'wintering' is not a problem on the mid west coast of Western Australia ! It is actually the best time for fishing - calm winds, bright warm sunny days, etc [I'll have to post some pictures !!] - the summer is the time for hotter days, stronger winds and shorter fishing trips before the afternoon sea breezes (20 knots ++) come in every day ...
I would love to get the 115hp EFI fourstroke or 115hp Optimax for the Montauk and pay the extra - BUT, I am informed by my local BW dealer, that this will void any warranties and marine insurance in the event of a claim. While the weight of the 115 is within the maximum motor weight, I would be caught by the maximum rated 90hp motor specified by BW and shown on their plate on the boat!
I have read threads on this forum with much larger motors on Montauks without problems - has BW looked to review this maximum 90hp rating ?
OzWhaler posted 07-27-2004 11:38 PM ET (US)     Profile for OzWhaler  Send Email to OzWhaler     
PS... I was interested to see that the 160 Dauntless is exactly the same weight and transom height as the 170 Montauk - yet BW has the Mercury 115hp motors as an option !!!
Camuyano posted 07-28-2004 11:08 AM ET (US)     Profile for Camuyano  Send Email to Camuyano     

That's a good question. I don't if BW could/would revise the maximum HP rating and what that would mean for boats already sold. It would be interesting to see what other members that are knowledgeable in this area think.

Some on this site have said that the reason for the hp rating is because the boat is meant to be sold as a package at a price point that many people can afford. The Montauk is meant to be a more "basic" boat than the Dauntless and that is probably why you can get more hp on the 160 even though it weighs the same as the Montauk.

As I said before, I think that the 90 4s is adequate on the 170 Montauk. I boat on a large open river and inland lakes and there are few days when I feel comfortable going wide open even with the 90 hp. I think that people here in the US are used to seeing bass boats and flats boats that are way overpowered. The logic being that if you can get to the fish faster you can fish longer; however, these boats are built for a specific purpose and are nowhere near as versatile as the 170. I have never ridden in one of these but people in the lake that we go to say that these boats are scary on anything but flat water and have read of bass boats almost being torn apart in a rough day in the Potomac.


bigjohn1 posted 07-28-2004 09:25 PM ET (US)     Profile for bigjohn1  Send Email to bigjohn1     
Another thing I factored into my decision NOT to go with the Optimax was its extensive computer system. I reasoned that way out here in the Western Pacific (Guam), the heat, humidity, and extremely high salinity, it would take a beating and possibly malfunction.
Big John

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