MONTAUK: 60-HP Four-stroke vs 90-HP Two-stroke

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Author Topic:   MONTAUK: 60-HP Four-stroke vs 90-HP Two-stroke

HAROSTRAIT posted 05-07-2005 02:09 PM ET (US)
Hello all. Does anyone have any feedback or performance data on the new YAMAHA 60-HP EFI four-stroke on a classic Montauk?
I am running a tired 1989 two-stroke 90-HP YAMAHA now. The new 60 EFI has 60.8 cubic inches (996cc), four cylinders, and 237 pounds compared to the two-stroke 90 69.6 cubic inches (1140cc), three cylinders, and 261 pounds. The new EFI 60 is also available in a high-thrust configuration. These numbers seem awfully close. Would higher the higher engine speed needed for cruise offset the fuel savings of the four-stroke? I primarily use the boat for fishing, and we take the boat as far as 27 miles out. It is, and will be, running a mid c.1995 Evinrude 15-HP two-stroke as a kicker.
I don't want to under power the boat or take away from potential resale value. Any feedback would be appreciated.
jimh posted 05-07-2005 07:18 PM ET (US)
With the weight of an auxiliary motor, you are probably looking at a top speed in the mid to high 30's.
A REFERENCE article tries to predict performance of the MONTAUK with a wide variety of motors:
http://continuouswave.com/whaler/reference/16-17/repower.html
Moe posted 05-07-2005 10:22 PM ET (US)
For the 950 lb weight of the Montauk, I'd opt for the high thrust version (2.33:1 gearing) with 14" diameter by 13" pitch prop. That's the same 996cc motor as the Mercury EFI Bigfoot we have on our 900 lb, but well-loaded 150 Sport. That gearing and prop turn just over 6,000 rpm at 32-33 mph, and cruises at 20 mph at 4,200 rpm (70% throttle).
--
Moe
The Chesapeake Explorer posted 05-07-2005 10:56 PM ET (US)
I would not go for the high thrust 60..Its for Pontoon boats. I checked this engine out well. Just repowered with a new Yamaha 90 2 Stroke. last yer to get one 261 pounds you know the rest/ The 60 Yamaha is a attractive motor, like you I did not want to be underpowered. The 90 2S will blow a 60 4S away in performance, You saw the CC diference,
Now for a quite ride, easy start good idel I am sure the 60 wins hands down.. actually the 90 2S is pretty good there too! If your going to get a 60 get the regular gear ratio you will need all the RPM you can get for the top end speed.
LHG posted 05-09-2005 01:44 PM ET (US)
Go to Whaler.com and look at the performance figures on the 170 Montauk. Although the boat is bit heavier, the information will be proportional, and it tells you everything you will want to know. The Yamaha 60 4-stroke is a Mercury powerhead, same as the Merc 60 EFI 4-stroke they test. The Yamaha 2-stroke 90 is not as strong as the Merc 2-stroke 90, which is more like a 100 HP engine.
Looking at those figures, I would not put a 60 on the boat.
elaelap posted 05-09-2005 10:49 PM ET (US)
I was very happy with a high thrust 50 hp Yamaha four stroke on my old Katama, but I used the boat 90% of the time in lumpy seas north of San Francisco, where top end speed was of absolutely no importance. Another consideration is that the smirkless 16s are maybe ten percent lighter than the smirked classic Montauks. If you're planning on making regular 27 mile runs in calm waters, maybe the 90 hp motor, either two- or four stroke, would be a better choice. My boat topped out at 'only' 30 mph/5900 rpm, and its comfortable cruising turns (3000-4000) kept me in the high teens and low twenties, which was perfect for the conditions in which I generally use my boat. One thing I loved with the high thrust configuration--that sweet old boat would jump instantly up onto plane and maintain plane at very low speeds, especially compared with my current Whaler, an Outrage 18, which also jumps right up onto plane but needs to be going almost twenty to stay on plane.
One more possible choice--many CW members have been very pleased with the Johnson/Suzuki 70 hp four stroke on their classic Montauks.
Tony
steelhead5 posted 05-10-2005 05:30 PM ET (US)
Im one of the very happy guys with the suzuki df70 4 stroke on the back of my boat. Its the perfect ocean going engine for this boat. Last week I ran in at 27 knots with 3 people on board in nice seas. The motor is a slam dunk on a montauk.
HAROSTRAIT posted 05-11-2005 01:40 AM ET (US)
People, thanks for the well thought out and informative responses to my query.
LHG, I should have done more research prior to my post regarding the Mercury/Yamaha connection. I am guessing that this may apply to the 4 stroke models?? As the 2 strokes appear to have a pronounced difference in weight between the 2 90's.
It seems that the Yam 90 or DF 70 is the way to go. I am also considering Johnson at this point as well, as it falls more into my price range than the DF 70. I am hoping to stay in the 5k range.
The 27 mile crossings that I make from the mouth of the Admiralty Inlet in Washington State, to the North end of San Juan Island on the Vancouver/US border, are best suited for a Montauk that has power to spare.
It sounds like a 60/4 stroke wouldn't have the reserve power or WOT that I need out there at times.
As a fisherman I appreciate the low fuel consumption and lower purchase/operating costs that the smaller hp models offer, but as a co Montauk owner (with twin OMC 50's) put it so succinctly "A Boston Whaler is a HIGH PERFORMANCE BOAT....why do it the injustice of underpowering it and compromising that performance?"
I think he is likely right.......
LHG posted 05-11-2005 01:38 PM ET (US)
The Yamaha 90 four stroke is only 10# heavier than the Suzuki 70. I would't worry about the 10 pounds, and get the 90 horses instead. There will be insignificant difference in economy, as both are EFIs.
But it's still hard to beat 2-stroke 90 power on a Montauk.
afishinado posted 05-11-2005 02:00 PM ET (US)
From what I've seen on 17's is that a 70 is ample power but a 90 if you like to go fast... My humble opinon here would be look at the D.I. 2 strokes.. Tohatsu makes one, and the E-tec would top my short list.

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Author	Topic: MONTAUK: 60-HP Four-stroke vs 90-HP Two-stroke
HAROSTRAIT	posted 05-07-2005 02:09 PM ET (US) Hello all. Does anyone have any feedback or performance data on the new YAMAHA 60-HP EFI four-stroke on a classic Montauk? I am running a tired 1989 two-stroke 90-HP YAMAHA now. The new 60 EFI has 60.8 cubic inches (996cc), four cylinders, and 237 pounds compared to the two-stroke 90 69.6 cubic inches (1140cc), three cylinders, and 261 pounds. The new EFI 60 is also available in a high-thrust configuration. These numbers seem awfully close. Would higher the higher engine speed needed for cruise offset the fuel savings of the four-stroke? I primarily use the boat for fishing, and we take the boat as far as 27 miles out. It is, and will be, running a mid c.1995 Evinrude 15-HP two-stroke as a kicker. I don't want to under power the boat or take away from potential resale value. Any feedback would be appreciated.
jimh	posted 05-07-2005 07:18 PM ET (US) With the weight of an auxiliary motor, you are probably looking at a top speed in the mid to high 30's. A REFERENCE article tries to predict performance of the MONTAUK with a wide variety of motors: http://continuouswave.com/whaler/reference/16-17/repower.html
Moe	posted 05-07-2005 10:22 PM ET (US) For the 950 lb weight of the Montauk, I'd opt for the high thrust version (2.33:1 gearing) with 14" diameter by 13" pitch prop. That's the same 996cc motor as the Mercury EFI Bigfoot we have on our 900 lb, but well-loaded 150 Sport. That gearing and prop turn just over 6,000 rpm at 32-33 mph, and cruises at 20 mph at 4,200 rpm (70% throttle). -- Moe
The Chesapeake Explorer	posted 05-07-2005 10:56 PM ET (US) I would not go for the high thrust 60..Its for Pontoon boats. I checked this engine out well. Just repowered with a new Yamaha 90 2 Stroke. last yer to get one 261 pounds you know the rest/ The 60 Yamaha is a attractive motor, like you I did not want to be underpowered. The 90 2S will blow a 60 4S away in performance, You saw the CC diference, Now for a quite ride, easy start good idel I am sure the 60 wins hands down.. actually the 90 2S is pretty good there too! If your going to get a 60 get the regular gear ratio you will need all the RPM you can get for the top end speed.
LHG	posted 05-09-2005 01:44 PM ET (US) Go to Whaler.com and look at the performance figures on the 170 Montauk. Although the boat is bit heavier, the information will be proportional, and it tells you everything you will want to know. The Yamaha 60 4-stroke is a Mercury powerhead, same as the Merc 60 EFI 4-stroke they test. The Yamaha 2-stroke 90 is not as strong as the Merc 2-stroke 90, which is more like a 100 HP engine. Looking at those figures, I would not put a 60 on the boat.
elaelap	posted 05-09-2005 10:49 PM ET (US) I was very happy with a high thrust 50 hp Yamaha four stroke on my old Katama, but I used the boat 90% of the time in lumpy seas north of San Francisco, where top end speed was of absolutely no importance. Another consideration is that the smirkless 16s are maybe ten percent lighter than the smirked classic Montauks. If you're planning on making regular 27 mile runs in calm waters, maybe the 90 hp motor, either two- or four stroke, would be a better choice. My boat topped out at 'only' 30 mph/5900 rpm, and its comfortable cruising turns (3000-4000) kept me in the high teens and low twenties, which was perfect for the conditions in which I generally use my boat. One thing I loved with the high thrust configuration--that sweet old boat would jump instantly up onto plane and maintain plane at very low speeds, especially compared with my current Whaler, an Outrage 18, which also jumps right up onto plane but needs to be going almost twenty to stay on plane. One more possible choice--many CW members have been very pleased with the Johnson/Suzuki 70 hp four stroke on their classic Montauks. Tony
steelhead5	posted 05-10-2005 05:30 PM ET (US) Im one of the very happy guys with the suzuki df70 4 stroke on the back of my boat. Its the perfect ocean going engine for this boat. Last week I ran in at 27 knots with 3 people on board in nice seas. The motor is a slam dunk on a montauk.
HAROSTRAIT	posted 05-11-2005 01:40 AM ET (US) People, thanks for the well thought out and informative responses to my query. LHG, I should have done more research prior to my post regarding the Mercury/Yamaha connection. I am guessing that this may apply to the 4 stroke models?? As the 2 strokes appear to have a pronounced difference in weight between the 2 90's. It seems that the Yam 90 or DF 70 is the way to go. I am also considering Johnson at this point as well, as it falls more into my price range than the DF 70. I am hoping to stay in the 5k range. The 27 mile crossings that I make from the mouth of the Admiralty Inlet in Washington State, to the North end of San Juan Island on the Vancouver/US border, are best suited for a Montauk that has power to spare. It sounds like a 60/4 stroke wouldn't have the reserve power or WOT that I need out there at times. As a fisherman I appreciate the low fuel consumption and lower purchase/operating costs that the smaller hp models offer, but as a co Montauk owner (with twin OMC 50's) put it so succinctly "A Boston Whaler is a HIGH PERFORMANCE BOAT....why do it the injustice of underpowering it and compromising that performance?" I think he is likely right.......
LHG	posted 05-11-2005 01:38 PM ET (US) The Yamaha 90 four stroke is only 10# heavier than the Suzuki 70. I would't worry about the 10 pounds, and get the 90 horses instead. There will be insignificant difference in economy, as both are EFIs. But it's still hard to beat 2-stroke 90 power on a Montauk.
afishinado	posted 05-11-2005 02:00 PM ET (US) From what I've seen on 17's is that a 70 is ample power but a 90 if you like to go fast... My humble opinon here would be look at the D.I. 2 strokes.. Tohatsu makes one, and the E-tec would top my short list.