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Author Topic:   More Merc 90 2-stroke/Montauk Numbers
Landlocked posted 05-05-2002 09:54 PM ET (US)   Profile for Landlocked   Send Email to Landlocked  
Well - finally got a good day on the river. Put 63.0 miles on the new motor today. Here are a few numbers. Water was smooth but swift - boat drifted downstream at 3.6 mph with the motor off Probably not an extremely accurate measurement of current given wind and drag but close.

Boat planes completely at 20.5 mph. I then back off to 17.5 mph without slipping off plane.

Traveling downstream with the current I noted the following speed vs. rpm's. All speed measurements GPS averaged over several minutes. Prop is 21" pitch merc black max.
Load Myself and dog - 300lbs. (he's a big dog) 24 gallons fuel @ start of trip.

21.5mph @ 2,950rpm
24.0mph @ 3,200rpm
26.0mph @ 3,400rpm
28.0mph @ 3,600rpm
30.5mph @ 3,800rpm
35.5mph @ 4,250rpm
38.0mph @ 5,000rpm
42.2mph @ 5,250rpm - WOT any more trim broke prop lose.

Traveling upstream the maximum speed I could get was 36.7 @5000 rpm which was completely trimmed out.

Fuel usage (based on float guage)

When I turned for the final run back to the dock guage showed 3/4 tank. When I arrived, 29.6 miles later guage showed 1/4 tank so I used approximately 6 gallons which = 4.93 mpg. Given the inherent inacuracies of float guages I would not hesitate to shave this down to 4.0mpg - good enough for me.

I tried my best to hold a speed of 22 (3200 rpm) the entire trip back but did open it up for a mile or two of this distance and came off plane twice while negotiating my way around a couple of barges.

Heading to Raleigh for a few days so I'll be out of pocket starting tomorrow. If I don't respond to replies - I'm not being rude.

See ya,


tabasco posted 05-07-2002 06:48 AM ET (US)     Profile for tabasco  Send Email to tabasco     
Have you considered running the boat with a Vengeance prop? should give you 2-4MPH difference.
Wild Turkey posted 05-07-2002 11:13 AM ET (US)     Profile for Wild Turkey  Send Email to Wild Turkey     

Sounds like you are OK... in my estimation. Maybe down to a 19" pitch prop. would get the rpm's to 5500 @ WOT.

What height is the motor? Maybe keep the 21" pitch prop and raise the motor slightly?

Personally, i think you are fine at 42.2 mph @ WOT if the boat is stable. My Montauk tops out at 44 mph (trimed out) and it is a handfull to drive at that speed and attitude. I think this hull was really not designed for speeds in excess of 50 mph.


kamml posted 05-07-2002 08:27 PM ET (US)     Profile for kamml  Send Email to kamml     
Sounds like you have it dialed in nicely. Enjoy. Ken
Landlocked posted 05-10-2002 08:28 PM ET (US)     Profile for Landlocked  Send Email to Landlocked     
Stopped on the way back from Raleigh at my brothers - had to log on and see what was up...

Motor is mounted 2holes up (1.5 inches). It is real squirrely already at that height. Probably don't want to raise it anymore.

Pretty happy with what I have but may check out the Vengence prop. Is that one of the surfacing props?

Will check back in when I get home tomorrow.


thebone12 posted 05-19-2002 05:19 AM ET (US)     Profile for thebone12  Send Email to thebone12     
here on long island, the bay police have a 17 montauk with a 1989 225 evinrude. No kidding, its all they had so they put them together. top speed is 62 mph and it is a monster out of the hole with very little porpose up to 56mph then it becomes a handfull!
whalernut posted 05-19-2002 09:45 AM ET (US)     Profile for whalernut  Send Email to whalernut     
If those Police Drink like they drive that Montauk, they must be party animals!!! I would love to see that 62mph first hand some day!! Jack.
Alan Hiccock posted 05-19-2002 10:54 AM ET (US)     Profile for Alan Hiccock  Send Email to Alan Hiccock     
If its the guys around Jones Inlet area that dock on Reynolds that boats an Outrage 18 I think { classic}.
Its got the 225 hp, I think they might be DEC guys.
It looks like a Montauk a little from a distance BUT Ive had them come over and talk to me 3 times this season when fishing.
Unless its another boat all together but maybe a CPD hull but a 17 with a 225?
geeze cant help but think that would be too much engine for the boat?

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