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Author Topic:   1982 "MANTAUK" with 125-HP

mercdivertsuperior posted 08-21-2008 10:49 AM ET (US)
I [may buy] a 1982 Mantauk with a 125-HP Mercury. [Is this boat] considered to be overpowered? I haven't seen the boat in the water yet so I don't know if it rides low in the stern. Thanks for any thoughts. Thanks for any advice.
Buckda posted 08-21-2008 12:07 PM ET (US)
Overpowered for what purpose?
By that I mean - for insurance purposes? For local law enforcement purposes? For weight purposes?
The boat is technically overpowered in that it has a HP that is over the capacity plate. That will affect your insurance. It may also have an effect in your interactions with law enforcement. It will impact lawsuits, etc. should you have an accident.
Is it too much power for the boat? I don't think so. Even if it's making full HP (which it may no longer be doing), the hull can handle the power, in the hands of an able-bodied captain.
Is it too much weight? Nah. Those Montauk hulls can handle a great bit of weight. Unless you put a fat heavy fourstroke on the back, you're in good shape. I've seen these boats with heavy Honda 90's and the E-TEC 115 and they wear the weight well.
The real question is about that 125 Merc. Is that a 2+2 engine? If so, you may want to test run it...the rumors are that the transition from 2 cylinders to 4 was rough...you may not like it.
Dave
mercdivertsuperior posted 08-21-2008 12:18 PM ET (US)
Dave,
Thanks for the input. My primary concern is seaworthiness of the boat which from what you say won't be adversely affected. The other issues you mention are worth considering too. Does anyone know the max horsepower rating on a Mantauk?
The reason I asked this question in the first place is because any Mantauks I've seen to date, whether in person or on line, were usually powered by motors under (perhaps just under) 100 hp.
Jim
Tohsgib posted 08-21-2008 12:21 PM ET (US)
Max hp is 100. I have seen them with 200's hanging off the transom. Biggest thing would be the 2+2 and they are kinda thirsty.
Perry posted 08-21-2008 12:26 PM ET (US)
What's a Mantauk? A Montauk for men?
mercdivertsuperior posted 08-21-2008 12:28 PM ET (US)
What is a 2+2 engine?
Jim
Buckda posted 08-21-2008 12:47 PM ET (US)
see: http://continuouswave.com/ubb/Forum4/HTML/004113.html
for some previous discussion on this motor. Note that forum member SOSMERC is a Mercury mechanic. Given his position as a mechanic and his comments in the thread, that motor may not be your cup of tea.
Additionally, note that forum member LHG is one of the most verdant Mercury supporters on the face of the planet. Just mentioning that you're not a fan of a Mercury usually causes his face to redden and his eyes to squint! Seriously though, he's a huge brand backer and he isn't impressed with this effort from the folks in Fond du Lac either.
You may want to consider a discount offer based on the engine! Definitely test drive before you buy.
Dave
mercdivertsuperior posted 08-21-2008 12:59 PM ET (US)
Upon visual inspection, how am I supposed to tell if this motor is a 2+2?
Tohsgib posted 08-21-2008 02:06 PM ET (US)
Dunno...I thought all 125's were 2+2's.
jimh posted 08-21-2008 08:38 PM ET (US)
Mercury made some four-cylinder engines which were very unusual. The engine runs on two cylinders at low speeds and then switches to all four cylinders at higher speeds. The transition was generally around 2,000-RPM. From reports of owners of these engines the transition was rather abrupt. When the second set of cylinders became active the motor really kicked in.
The technique for shutting off the two cylinders at low speed was very simple. The carburetors feeding those cylinders did not have any low-speed orifices.
My impression of those motors based on accounts from people who have owned and operated them is that the motors were strong motors, but they did not have a smooth throttle response, and the idle and transition speed were generally characterized by roughness.
The descriptor "2+2" is used to describe these motors. They were sold in 115-HP and, apparently, also in 125-HP models.
A four-cylinder in-line motor is inherently a rough motor, as that configuration is not naturally balanced. More sophisticated motors--not these simple Mercury ones--uses balancing weights to counteract the vibrations and imbalance inherent in an in-line four-cylinder design. When you drop off two cylinders and just run on two cylinders, the roughness increases.
As far as I know no other manufacturer ever made a 2+2 motor, although other manufacturers have made motors which shut off a cylinder or two cylinders at low speed ranges. Mercury never made another motor with this 2+2 technique.
A two-cycle motor is difficult to idle down, and by using the 2+2 technique Mercury was able to make these motors run at idle speeds.
In contrast, three-cylinder motors generally never have any cylinders shut off for idle. A three-cylinder motor seems to be much better balanced and can run smoothly at idle. The in-line four cylinder motor was something generally not used in outboards--except for these Mercury 2+2 motors--until recently when a new generation of four-cylinder four-cycle motors were introduced in the 150-HP range. However, most of these four-cylinder motors have balancing shafts and counterweights to reduce vibration and roughness inherent in the in-line four-cylinder configuration.
jimh posted 08-21-2008 08:44 PM ET (US)
A Boston Whaler MONTAUK 17 with 125-HP would be powered above the rated maximum. You can slice and dice the semantics as much as you want, but that is "over-powered" under any interpretation.
mercdivertsuperior posted 08-22-2008 08:33 AM ET (US)
Thanks everybody for the info/advice.
Jim

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Author	Topic: 1982 "MANTAUK" with 125-HP
mercdivertsuperior	posted 08-21-2008 10:49 AM ET (US) I [may buy] a 1982 Mantauk with a 125-HP Mercury. [Is this boat] considered to be overpowered? I haven't seen the boat in the water yet so I don't know if it rides low in the stern. Thanks for any thoughts. Thanks for any advice.
Buckda	posted 08-21-2008 12:07 PM ET (US) Overpowered for what purpose? By that I mean - for insurance purposes? For local law enforcement purposes? For weight purposes? The boat is technically overpowered in that it has a HP that is over the capacity plate. That will affect your insurance. It may also have an effect in your interactions with law enforcement. It will impact lawsuits, etc. should you have an accident. Is it too much power for the boat? I don't think so. Even if it's making full HP (which it may no longer be doing), the hull can handle the power, in the hands of an able-bodied captain. Is it too much weight? Nah. Those Montauk hulls can handle a great bit of weight. Unless you put a fat heavy fourstroke on the back, you're in good shape. I've seen these boats with heavy Honda 90's and the E-TEC 115 and they wear the weight well. The real question is about that 125 Merc. Is that a 2+2 engine? If so, you may want to test run it...the rumors are that the transition from 2 cylinders to 4 was rough...you may not like it. Dave
mercdivertsuperior	posted 08-21-2008 12:18 PM ET (US) Dave, Thanks for the input. My primary concern is seaworthiness of the boat which from what you say won't be adversely affected. The other issues you mention are worth considering too. Does anyone know the max horsepower rating on a Mantauk? The reason I asked this question in the first place is because any Mantauks I've seen to date, whether in person or on line, were usually powered by motors under (perhaps just under) 100 hp. Jim
Tohsgib	posted 08-21-2008 12:21 PM ET (US) Max hp is 100. I have seen them with 200's hanging off the transom. Biggest thing would be the 2+2 and they are kinda thirsty.
Perry	posted 08-21-2008 12:26 PM ET (US) What's a Mantauk? A Montauk for men?
mercdivertsuperior	posted 08-21-2008 12:28 PM ET (US) What is a 2+2 engine? Jim
Buckda	posted 08-21-2008 12:47 PM ET (US) see: http://continuouswave.com/ubb/Forum4/HTML/004113.html for some previous discussion on this motor. Note that forum member SOSMERC is a Mercury mechanic. Given his position as a mechanic and his comments in the thread, that motor may not be your cup of tea. Additionally, note that forum member LHG is one of the most verdant Mercury supporters on the face of the planet. Just mentioning that you're not a fan of a Mercury usually causes his face to redden and his eyes to squint! Seriously though, he's a huge brand backer and he isn't impressed with this effort from the folks in Fond du Lac either. You may want to consider a discount offer based on the engine! Definitely test drive before you buy. Dave
mercdivertsuperior	posted 08-21-2008 12:59 PM ET (US) Upon visual inspection, how am I supposed to tell if this motor is a 2+2?
Tohsgib	posted 08-21-2008 02:06 PM ET (US) Dunno...I thought all 125's were 2+2's.
jimh	posted 08-21-2008 08:38 PM ET (US) Mercury made some four-cylinder engines which were very unusual. The engine runs on two cylinders at low speeds and then switches to all four cylinders at higher speeds. The transition was generally around 2,000-RPM. From reports of owners of these engines the transition was rather abrupt. When the second set of cylinders became active the motor really kicked in. The technique for shutting off the two cylinders at low speed was very simple. The carburetors feeding those cylinders did not have any low-speed orifices. My impression of those motors based on accounts from people who have owned and operated them is that the motors were strong motors, but they did not have a smooth throttle response, and the idle and transition speed were generally characterized by roughness. The descriptor "2+2" is used to describe these motors. They were sold in 115-HP and, apparently, also in 125-HP models. A four-cylinder in-line motor is inherently a rough motor, as that configuration is not naturally balanced. More sophisticated motors--not these simple Mercury ones--uses balancing weights to counteract the vibrations and imbalance inherent in an in-line four-cylinder design. When you drop off two cylinders and just run on two cylinders, the roughness increases. As far as I know no other manufacturer ever made a 2+2 motor, although other manufacturers have made motors which shut off a cylinder or two cylinders at low speed ranges. Mercury never made another motor with this 2+2 technique. A two-cycle motor is difficult to idle down, and by using the 2+2 technique Mercury was able to make these motors run at idle speeds. In contrast, three-cylinder motors generally never have any cylinders shut off for idle. A three-cylinder motor seems to be much better balanced and can run smoothly at idle. The in-line four cylinder motor was something generally not used in outboards--except for these Mercury 2+2 motors--until recently when a new generation of four-cylinder four-cycle motors were introduced in the 150-HP range. However, most of these four-cylinder motors have balancing shafts and counterweights to reduce vibration and roughness inherent in the in-line four-cylinder configuration.
jimh	posted 08-21-2008 08:44 PM ET (US) A Boston Whaler MONTAUK 17 with 125-HP would be powered above the rated maximum. You can slice and dice the semantics as much as you want, but that is "over-powered" under any interpretation.
mercdivertsuperior	posted 08-22-2008 08:33 AM ET (US) Thanks everybody for the info/advice. Jim