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Author Topic:   1985 Montauk Re-Power
whalerski posted 10-15-2001 12:43 PM ET (US)   Profile for whalerski   Send Email to whalerski  
I wish to re-power a 1985 Montauk. Existing is a 1985 Suzuki 85-HP good top end terrible idle and low rpm carbs difficult and must tune using unique tool, but engine still runs well. Wish to change. Looking at fouyr-cycle engines-only and trying to stay at upper end of [the rated horsepower]. [Solicits readers'] thoughts on Yamaha, Honda, Mercury, or other listed by order of present thought on my part.

Also, where might find late model or new 200 to mitigate investment?

OutrageMan posted 10-15-2001 02:09 PM ET (US)     Profile for OutrageMan  Send Email to OutrageMan     
There is a NAUSET in our harbor that just re-powered with a Yamaha 85-HP 4 stroke. There is little smoke, and the starter makes more noise than the engine. The owner reports that it is a great preformer.

Brian

JBCornwell posted 10-15-2001 03:18 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
You will have a lot more weight than was contemplated when laying out your Montauk if you go with a 360-lbs engine, Whalerski. When they rated it for 100-HP they thought about the big OMC V4s which come in at a bit over 300 pounds.

I repowered last Spring, ending up, after extensive research and a dozen interviews, with a Suzi DF70 (338#). It was the only EFI 4 stroke in the class at the time ('Rudes don't count because they are Suzis with different decals). I had to move the battery to the console to get it balanced to my liking. It will WOT at 38mph (GPS) and cruise at 30 (5000 rpm).

I am happy with it, but if I had it to do over I would look a lot closer at the DF50. It is 100 pounds lighter and will run a Montauk at 35-36mph WOT and still cruise at 28-30.

I am a fisherman and no longer get aroused by surplus power and neck-snapping hole shots. If you like hairy chested performance and are willing to have your boat run bow-high at full plane then go for the Yammy 100. It is the best option (356#) in a 90-100hp 4 stroke.

Red sky at night. . .
JB :)

TightPenny posted 10-15-2001 05:07 PM ET (US)     Profile for TightPenny  Send Email to TightPenny     
My 2000 Montauk runs very nicely with a 90hp Johnson. There are still some good deals out there on Johnsons.

You might get better fuel mileage with the 4 strokes, but just how long do you have to run it to pay for the difference?

Such posted 10-15-2001 08:41 PM ET (US)     Profile for Such  Send Email to Such     
Red Sky, I found your comment about the 50hp interesting, is that based on an actual setup or an educated guess? I am interested because, I am close to closing a deal on a 70hp, the weight has always concerned me.
JBCornwell posted 10-15-2001 08:59 PM ET (US)     Profile for JBCornwell  Send Email to JBCornwell     
Some of each, Such. While sightseeing in Sturgeon Bay, WI last Summer I was cruising at about 30 when a Montauk powered by the 'Rude version of the DF50 passed me rather smartly, so I had to pace her to see what she was doing. The teenage looking girl was alone and clearly showing me what she could do, which was 35 (GPS). There were three in my Sunshine III and I had to try hard to pace her.

I later used the formula for predicting performance that I got here, from Clark, to predict 35mph for the Montauk at 1600 pounds gross: 50hp/1600lb=.03125, square root of that is: 0.176776695 X 200 (constant for semi-flat bottom) = 35.36mph.

Clark's formula is spookily accurate.

Red sky at night. . .
JB :)

dgp posted 10-15-2001 09:15 PM ET (US)     Profile for dgp  Send Email to dgp     
You might find this thread informative http://continuouswave.com/ubb/Forum4/HTML/000013.html
Dick posted 10-15-2001 09:45 PM ET (US)     Profile for Dick  Send Email to Dick     
Montauk performance figures.
1999 17 Montauk, Merc 50 hp 4 stroke (not a big foot), downriggers, stern seat, cooler seat, 25 gallons fuel, electric trolling motor and probably another 400 lbs on board. Motor mounted up two holes and running a 13 pitch prop.
Very quick on plane.
Comfortable cruise at 25 mph.
Max speed trimmed out 32 mph per GPS
@ 5800 rpm.

With a lighter load I could probably pick up a mph or two, but let's be realistic we all load our boats heavier than than the optimum for performance. I am OK with the performance with the 50, but if you want to get into the 35+ mph range kick up the hp.

Mort posted 10-15-2001 10:41 PM ET (US)     Profile for Mort  Send Email to Mort     
Is your prop a stainless or aluminum?
John from Madison CT posted 10-16-2001 07:49 AM ET (US)     Profile for John from Madison CT  Send Email to John from Madison CT     
Dick,

How did you mount downriggers on your Montauk?

Thanks,

John

Dick posted 10-16-2001 10:27 AM ET (US)     Profile for Dick  Send Email to Dick     
My performance run was done on a calm lake, no wind and running a Merc 13 pitch SS Vengance.

I am using Scotty swivel bases and rail mounts for the downriggers. John I'll e-mail you a picture of the set up.

Dick

jellisfeingold posted 10-16-2001 12:39 PM ET (US)     Profile for jellisfeingold  Send Email to jellisfeingold     
We are real happy with a Honda 50hp 4-stroke on our 17' Montauk. The boat is set-up pretty basic: console, teak box/seat, and cooler seat. It'll run about 32mph @ 6,000 rpm, and planes quickly. Since we're on choppy salt (Long Island Sound), we're not at WOT too often for too long. This engine has plenty of mid-throttle grunt.
gvisko posted 10-16-2001 06:43 PM ET (US)     Profile for gvisko  Send Email to gvisko     
the most i can get out of my suzuki 70hp
4 stroke is 34 mph wot on wass gps
this is by myself with stainless prop
and 26 gallons of gas i am about 260lbs
if you can get this with a 50 that might
be the way to go i have no regrets with the 70 i think its a great motor.


gvisko


dchapp posted 10-17-2001 10:30 AM ET (US)     Profile for dchapp  Send Email to dchapp     
just repowered my 85 with a yamaha 4s 100. This was completed approx 3 weeks ago. I am not certain I am proped right, but I can get about 45mph top end. Very quiet.
Bigshot posted 10-17-2001 01:27 PM ET (US)     Profile for Bigshot  Send Email to Bigshot     
What did you have before the 100? How does it sit and perform?
dchapp posted 10-17-2001 03:27 PM ET (US)     Profile for dchapp  Send Email to dchapp     
I bought the boat with a johnson 90 that was in a sad state, I ran it twice and decided to replace it. Does not appear to sit any different in water, although again I did not have alot of time with it before I replaced the engine.
Traveller posted 10-19-2001 08:18 PM ET (US)     Profile for Traveller  Send Email to Traveller     
I've seen several posts about the four-stroke 50, and when I begin to put together a Montauk package I am strongly considering that motor. Would performance improve enough with the four-stroke 60 to justify whatever the difference in expense would be?
Highwater posted 10-19-2001 09:51 PM ET (US)     Profile for Highwater    
Most people feel that their engine either has just the right amount of horsepower or not quite enough. People rarely complain that their engine has too much horsepower.

I like the Honda 90, which is incredibly quiet, weighs the same as the Honda 75, and costs slightly less than the Honda 75 ($5825—see http://www.outboardodyssey.com/honda.htm)

Cruiser posted 10-20-2001 02:26 PM ET (US)     Profile for Cruiser    
Wow, if you are going to put that much engine weight on a Montauk make sure you get enough horsepower out of the engine. If I was in the market for a used Montauk I certainly would pass right by the ones with 50 - 70 hp on them, even if they were 4 strokes! Get a fuel injected 2 stroke and make it go more than 35mph!
Kelly posted 10-21-2001 01:42 PM ET (US)     Profile for Kelly  Send Email to Kelly     
Here is a table based on Clark's formula for the Montauk. I thought it was interesting. Fuel weight used was 168, boat weight used was 950, gear and passengers weight 400, motor weight does not include prop. I assumed the props to be very close in weight and included in the gear and passengers number. How does this compare with people's experience? To summarize, it appears that a 50 is good for low 30's, a 70 will get you into the upper 30's, but it takes a 90 or better to get into the low to mid 40's. Kelly

Motor     mtr     tot    speed
wt wt (mph)

H50-4 212 1730 34
H90-4 373 1891 44
Y50-4 233 1751 34
Y60-4 244 1762 37
Y100-4 356 1874 46
Y50-2 194 1712 34
Y60-2 228 1746 37
Y70-2 228 1746 40
Y90-2 261 1779 45
M50-4 236 1754 34
M60-4 236 1754 37
M90-4 386 1904 43
M50-2 199 1717 34
M60-2 219 1737 37
M75-2 303 1821 41
M90-2 303 1821 44
S50-4 243 1761 34
S70-4 359 1877 39

Kelly posted 10-21-2001 01:57 PM ET (US)     Profile for Kelly  Send Email to Kelly     
Well, the above post did not appear as intended. The first part is the motor, ie H50-4, the second number is the motor weight, the third number is the total weight, and the last number is the mph. Kelly
jpgbu1 posted 02-21-2011 10:35 AM ET (US)     Profile for jpgbu1  Send Email to jpgbu1     
[Revived this discussion after it had been dormant for over ten years. Please start a new thread instead.--jimh]

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