1986 NEWTAUK E-TEC 90

Optimizing the performance of Boston Whaler boats
bghaggar
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1986 NEWTAUK E-TEC 90

Postby bghaggar » Fri Aug 21, 2020 6:01 pm

[An E-TEC 90-HP outboard engine is model number ] E90DPGLAFD] [and also has a number] 5493829 [associated with it].

Boston Whaler 1987 Newport has a Montauk center console. [This is known as a NEWTAUK—Moderator]

I recently bought this boat and re-powered it with an E-TEC 90.

I previously had a 1979 Montauk [17] with both a 2004 and a 2017 E-TEC.

On the NEWTAUK the E-TEC is mounted one hole up and has a VIPER 19 propeller. The installing dealer said it was running at about 5,800-RPM and 40-MPG SOG. This is quite a bit higher engine speed than my previous boat—also with the 19 pitch VIPER but the engine on that boat was mounted in the lowest position; that mounting height is wrong for the E-TEC 90.

EV diagnostics before running the boat says maximum engine speed was 5,698-RPM.

just ran the boat for the first time and didn't have the diagnostic software during the run. Later the diagnostic software showed an increase in time between 5000 and 5500 and an increase between 5500 and 6000.

The Evinrude tachometer also said max at 5800-RPM.

I don’t know what to make of this.

On this website with similar boat-motor configurations the VIPER 19 should be okay.

[My test was with] two people approx 400 lbs, not much gear, about 6 gallons of [fuel]—so a light load.

Suggest a better prop that will reduce the engine speed closer to the desired 5200-RPM.

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Phil T
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Re: 1986 NEWTAUK E-TEC 90

Postby Phil T » Sat Aug 22, 2020 10:07 am

The E-TEC 90 hp engine has a WOT range of 5000-5500. Why do you want to reach 5200?

Owners with a classic 17' hull (Montauk, Newtauk, Standard) with an E-TEC 90hp engine have tested various props and engine heights.

Recommendations of propellers for this boat model/engine setup from this 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
13-1/4" x 17” Turbo 1
* Prop sizes only apply to specific make and model listed above. Engine should be mounted "two holes up", top bolt in the 3rd hole down from the top.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
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bghaggar
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Re: 1986 NEWTAUK E-TEC 90

Postby bghaggar » Sun Aug 23, 2020 3:20 pm

Phil T.
Thanks for the response. Just in answer to your first question - I think it's generally accepted on here (see the Sakonnet post below) that 5000 to 5200 is ideal. Youre correct about the 5000 to 5500 recommendation. And thanks for the prop input. Reason I posted is that this boat is different from my previous Montauk (same hull) in that it's heavier at the bow due to the additional fiberglass. At one hole up the anti-cav plate is above the water so the mounting should be correct. I was just surprised to see the 5700 hundred rpm on the hull since same prop on my montauk and almost every post here and on the etec forum has a lower max rpm with that prop. combination. I do have experience with 3 of the 5 props you mention (and I don't think you can get the SST anymore). I mostly wondered if any of the props you mentioned should lower the max rpm. From what I've seen only the stiletto might - don't know about the rogue but most don't recommend the 4 bladed props.

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Phil T
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Re: 1986 NEWTAUK E-TEC 90

Postby Phil T » Sun Aug 23, 2020 3:58 pm

I think you are confusing the location of the anti-cavitation plate. The [gear case foil] I am referring to is the one just above the propeller .

Your performance numbers read like something is off. I would expect 42 to 43-MPH at 5400 to 5500-RPM at two-holes-up engine mounting height.

Has the propeller been repaired ancb altered, or s the propeller new-in-box?
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
Member since 2003

bghaggar
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Re: 1986 NEWTAUK E-TEC 90

Postby bghaggar » Sun Aug 23, 2020 6:18 pm

Phil T,
We're talking about the same thing: it's the anti-ventilation plate and it's right at the surface of the water when planing with spray around it—not dry. And I think that's correct.

The propeller is as new as the engine—not even an hour on both yet.

I'll have the boat in the water later this week and confirm all of that data, including boat speed, with a full fuel load if the water is calm.

Unfortunately underway I don't have a NMEA network installed yet, so I can only go by the tachometer on the boat. Afterwards I compare the engine speed history data. I can't reset the maximum engine speed on the engine history.

The other problem: propellers are hard to get these days.

And I do agree that things aren't quite right, as otherwise I wouldn't be posting on here.

One other note: this hull was in fresh water all its life and on lifts. The hull might be lighter than some of the others (including the one I had before).

The installing dealer agreed that [the high engine speed at full throttle] was unusual. The dealer had a laid-off Evinrude technician working for him.

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Phil T
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Re: 1986 NEWTAUK E-TEC 90

Postby Phil T » Sun Aug 23, 2020 6:51 pm

I would go up 2 inches in pitch on the same make/model of prop to drop your rpm's. For each 1" of pitch expect a drop of ~ 300 rpm's.

In going back in the archives, I see several owners replaced the 19" BPR Viper with the 15" Stilletto. See Crabby's comments: http://continuouswave.com/ubb/Forum4/HTML/008110.html

It is Jim Hebert who offered the suggestion that 5000-5200 is the sweet spot in an archived thread. I think the sweet spot is higher.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
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jimh
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Re: 1986 NEWTAUK E-TEC 90

Postby jimh » Mon Aug 24, 2020 8:47 am

The notion of an optimum engine speed at full throttle for the E-TEC engine comes from Evinrude literature. It varies with the engine model AND the engine model year.

My own deduction is the recommended engine speed is the speed range for peak torque output. Peak torque typically will be at a lower engine speed than the maximum permitted engine speed.

I compiled a listing of engine speed recommendations in a REFERENCE article I wrote several years ago. All the data came from Evinrude literature. See

http://continuouswave.com/whaler/refere ... neRPM.html

I wrote the article 13-years-ago in 2007, and last updated the listings in 2013. I don’t have data for 2019 or 2020 models.

The three-cylinder E-TEC has a strange history of EPA Test Data submissions. In the EPA data over the years the 90-HP model has produced quite a range of output power. In some years it was down to about 84-HP, and in other years up to 90-HP. The reason for the variation is unknown to me, but I infer the changes were probably related to emission compliance. In c.2009 there was a change in fuel direct-injectors to the ball-in-line (BIP) design. This probably affected the tuning and the horsepower, too.

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Re: 1986 NEWTAUK E-TEC 90

Postby jimh » Mon Aug 24, 2020 9:06 am

The nature of the E-TEC engine power output is to have a rather wide engine speed range in which the rated power will be produced. This contrasts with other outboard engines like many high-revving four-stroke-power-cycle models which only reach a peak power output at the very top of their allowed engine speed range.

The result is the E-TEC engine speed does not always change as much as might be expected with higher or lower propeller loads. Propeller selection can be a bit more difficult to predict.

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NEW TOPIC: Plots of Horsepower and Torque

Postby Don SSDD » Tue Aug 25, 2020 6:30 am

ASIDE: To find horsepower and torque curves for outboard engine to see the RPM range where the power is available seems hard.
1986 Outrage 18 with 2001 Honda 130 HP
Former Owner 1991 Guardian 19 with 1994 Evinrude V4 140HP
Former owner 1987 Montauk with 1998 Mercury 90HP
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jimh
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Re: Plots of Horsepower and Torque

Postby jimh » Tue Aug 25, 2020 7:04 am

ASIDE: Most outboard engine manufacturers do not publish torque or horsepower plots as a function of engine speed. Very occasionally such a plot may be shown in presentations at internal meetings.