Montauk 17 E-TEC 90

Optimizing the performance of Boston Whaler boats
mikepte
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Joined: Thu Jan 14, 2021 1:30 pm

Montauk 17 E-TEC 90

Postby mikepte » Mon Jan 25, 2021 11:27 am

My 1984 MONTAUK 17 is being re-powered with a new E-TEC 90.

My current Evinrude V4 90 crossflow is mounted using the blind holes. The new E-TEC 90 engine cannot be mounted with blind holes.

Because my MONTAUK 17 hull has the shallow splash well, [the standard engine mounting hole location for the lower mounting holes] cannot be used (because the bolts will not be above the bottom of the splash well].

[The transom of the MONTAUK 17 will get new lower engine mounting holes drilled. The new lower engine mounting holes will be in a NON-STANDARD position, with a vertical spacing from the top hole pair of only 7-1/4-inches instead of the standard spacing of 8-inches. See the article in the ANNOUNCEMENT section of the forum for a diagram showing hole layout position and explanations of the options at http://continuouswave.com/forum/viewtopic.php?f=7&t=5808. The non-standard lower hole position to be used is shown in a diagram in that article with the holes marked as] yellow holes. [With this lower engine mounting hole location the engine mounting height can be] one-hole-up, two-holes-up, or three-holes-up, but not all the way down.

After reviewing numerous posts on this topic and in the absence of a Stiletto Advantage I in 13.25 x 15-pitch, I've narrowed my - starting propeller choice a BRP Viper in 13-7/8 x 17-pitch.

The boat will typically have myself and one other adult, 12-gallons of fuel, and a 100-slb of Rhodesian Ridgeback dog aboard.

I have seen various recommendations for the Viper propellers in the archives but the more current posts seem to favor the 17- pitch viper.

Does [a VIPER 17-pitch for an E-TEC 90 on a MONTAUK 17] sound like a good starting point?

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Phil T
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Re: Montauk 17 prop - E-TEC 90

Postby Phil T » Mon Jan 25, 2021 1:11 pm

The list of recommended props for the Montauk 17 with an E-TEC 90 from owners testing include:

13.25x19 Stiletto ADVANTAGE 1
13.5 x 20” Raker
13-7/8" x 19” BRP Viper
13-1/4" x 19” SST (2 holes up)
13-1/4" x 17” Turbo 1

I would mount the engine 3 holes up unless you pick the SST prop listed above.
**Note size is restricted to make and model listed only.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

jimh
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Re: Montauk 17 E-TEC 90

Postby jimh » Mon Jan 25, 2021 2:46 pm

Regarding the E-TEC legacy 90-HP three-cylinder engine, the engine power output rating used in the EPA emission testing that qualified the engine to be sold as meeting the EPA regulations in effect at the particular production epoch tended to vary over the years, probably due to considerations such as meeting the regulations in effect at that time or to meet other regulations such as those in the European Union or other regulatory bodies. I mention this not in regard to the emissions but in regard to the horsepower output of an E-TEC 90, which apparently varied from year to year over a range as low as 82-HP (if my recall is correct) to a high of 89-HP, or a variation of about 6-HP. This could introduce some variation in propeller selection, albeit probably not a huge variation.

Another element of the E-TEC 90 (and really any E-TEC engine) that must be considered on a model-year basis is the manufacturer's recommended optimum full-throttle engine speed range. This is the speed range where the engine torque output probably peaks, and faster RPM does not deliver more torque. Since horsepower is a product of torque and engine speed, the horsepower rating of the engine may remain the same while the torque decreases, as the increasing engine speed makes up for the reducing torque.

As a general goal in selecting a propeller for an E-TEC, aiming for the engine speed at full throttle to be in the recommended optimum engine speed range is probably a good approach. I have compiled a list of E-TEC engine recommended speed ranges and published them in the website's REFERENCE section at

E-TEC Recommended Engine Speed Range
http://continuouswave.com/whaler/reference/ETEC_EngineRPM.html

Over the years the E-TEC 90 has remained with an optimum engine speed range of 5,000 to 5,200-RPM. That speed range ought to be used as the goal when evaluating a propeller if you want to get the most performance from the E-TEC 90.

ASIDE: one influence on the engine speed ranges for the E-TEC was probably the fuel injector; there was a major change in fuel injector design across the E-TEC platform in 2008 and 2009. The voice-coil fuel injectors, themselves a somewhat unique design, changed to a new variation called the Ball-in-plunger or BIP design in c.2008. For other year-to-year changes I have also written an article on that topic:

E-TEC Model Year Changes
http://continuouswave.com/whaler/reference/ETEC_ModelYearChanges.html

The E-TEC 90 was a very popular choice for re-powering a MONTAUK 17, and I am certain you will be pleased with the engine. The size is very similar to traditional two-stroke-power-cycle engine sizes in the 90-HP range, whereas four-stroke-power-cycle engines at the time of the E-TEC 90 introduction (in c.2003) tended to have cowlings that were the size of 200-HP engines.

mikepte
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Re: Montauk 17 E-TEC 90

Postby mikepte » Mon Jan 25, 2021 8:05 pm

Thank you both for the input and quick response.

Phil - many of the recommendations in the archives were for a 13.25 x 15 Stiletto Advantage I so i was initially surprised to see the 19 pitch in the table of recommended props.

Is this simply a function of the outboard HP variance over the years?

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Phil T
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Re: Montauk 17 E-TEC 90

Postby Phil T » Mon Jan 25, 2021 8:40 pm

This came from Dave's post at the bottom of this thread: http://continuouswave.com/ubb/Forum4/HTML/004278.html

Buckda posted 06-05-2009 11:43 AM ET (US) Profile for Buckda Send Email to Buckda
I would like to append this discussion with some additional results in testing a 13.25x15 Stiletto ADVANTAGE 1 vs. 13.25x19 Stiletto ADVANTAGE 1 on a Montauk with 90-HP E-TEC.
This information is reported by Terry Hoy on his 1989 Montauk with 2005 E-TEC 90 HP motor. 10 gallons of fuel, one person aboard, speed via GPS.

15-pitch prop:
19.3 MPH at 3,000 RPM
42.4 MPH at WOT - 5,700 RPM

19-pitch prop:
22.7 MPH at 3,000 RPM
44.5 MPH at WOT - 5,200 RPM [<---the ideal full-throttle speed--jimh]

This is right in line with the performance of the classic cross-flow and loop charged OMC 90's on these hulls.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

mikepte
Posts: 3
Joined: Thu Jan 14, 2021 1:30 pm

Re: Montauk 17 E-TEC 90

Postby mikepte » Tue Jan 26, 2021 11:53 pm

Phil and Jim - thank you both for the comprehensive feedback.

I had not seen that post by Dave. I agreed with the rigger that we would start with the engine mounting height at three-holes-up, and then adjust the engine mounting height if needed.

When I get the propeller and mounting height dialed-in, I will report the outcome.