Mercury OptiMax Engine: Noise Signature, Smoothness

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jjdiv posted 12-06-2006 03:17 PM ET (US)
I would apppreciate hearing about any experiences with a model-year 2000 Mercury OptiMax 135-HP engine with 50-hours of running time. [Give it a rating on a scale of] 1 to 10. How smoothly do [135-HP Mercury OptiMax engines] run across the RPM range? How noisy is [a 135-HP Mercury OptiMax engine] at headway speeds? Thanks!
sosmerc posted 12-06-2006 10:49 PM ET (US)
If you compare a 2000 135 Optimax to just about ANY of the newer engines, whether 2 stroke or 4 stroke, you are going to find it is rather noisey. I work on Mercs for a living (for over25 years) and I am a die-hard Merc fan...AND I own a 1998 135 Optimax...BUT, I do not like the sound of ANY of the 2.5 litre Optimax engines. Merc knows they have a problem and I hear they are working on it and will soon introduce quieter models. But that doesn't help you or me.
The Optimax 135 is a strong performer as far as power and efficiency. The sound quality at idle is ok, and even at WOT, though loud, it isn't unpleasant. But at Mid-range there is a particular resonance that I find offensive and others have commented as well. The 1.5 litre and 3.0 litre models are different and I don't mind them at all. In fact, the 3 cylinder 1.5 litre Optimax engines appear to be just as quiet as the new 115 4 stroke Merc.
If you are contemplating buying a used boat with an older Optimax 135, you need to go for a ride and judge for yourself whether or not you would want to cruise for an hour with that noise behind you.
sosmerc posted 12-07-2006 12:08 AM ET (US)
Some noise comparison taken from Whaler provided performance data:
135 Optimax at 600 rpm.........82 dB(A)
115 Merc 4 stroke @ 600 rpm....59 dB(A)
135 Optimax at 3000 rpm.......102 dB(A)
115 Merc 4 stroke @ 3000 rpm..91 dB(A)
135 Optimax at 5500 rpm.......105 dB(A)
115 Merc 4 stroke @ 6100 rpm..101 dB(A)
BUT...the 135 Optimax got a 3469 lb. Ventura to 30mph in 5.8 seconds
While it took the 115 4 Stroke 10 seconds to get a 2967 lb Montauk to 30 mph.
So as you can see, there is always some give and take. If Mercury can get the larger Optimax engines into the 4 stroke "quiet zone" they will really have something to brag about!!
jimh posted 12-07-2006 01:12 AM ET (US)
A Mercury mechanic (that I judged to be quite earnest and experienced) told me that he liked the 2.5-liter OptiMax engines because of their excellent record of few problems with power head failures. The larger displacement, 3.0-liter OptiMax engines have been more problematic, and this has given the whole OptiMax engine line a bit of baggage to carry around.
The 135-HP engine is the mild tuning version; this same engine can produce up to 175-HP as an OptiMax, and much more as a race-tuned motor.
The OptiMax motors have been tested recently and have shown best-in-class performance in terms of power and fuel economy.
The older OptiMax motors were designed and manufactured at a time when noise, vibration, and harshness (NVH) were not as prominent in the buyer's selection criteria as they are now, and, as a result, these motors are not as quiet as many current designs. If noise is an important criterion, you must give this engine a careful listen to see if it will be acceptable to you.
As with any used mechanical device, the condition is of paramount concern. This will have the biggest influence on a decision to buy or not.
It is also often recommended that the engine's history be checked with the manufacturer to verify if there were any field service bulletins, upgrades, recalls, engineering changes, etc., that were issued for the motor and whether or not they were performed on this particular motor. A cooperative Mercury dealer should be able to assist you with that inquiry.
Clark Roberts posted 12-07-2006 08:53 AM ET (US)
I agree with the above responses and will add my experience with my 2000 Opti 135. I put over 500 hours on it on a 1979 Revenge 21 and it performed flawlessly and only time in shop was for a fuel injector upgrade. It felt like a 175hp with a savage hole shot and it would run 46mph at full throttle and got 5.5mpg at a 30 mph cruise. My complaints (other than the noise as mentioned above) was a hot idle. At idle it would run hot enough to set off the overheat buzzer on occasion. I replaced the factory 143degree thermostats with 120 degree (not recommended since the colder idle creates more polution I'm told) and problem solved. Later I put the 143's back in cut a loop off the poppet balve spring so that it opened with less press...again problem solved. I put in new plugs at about 200 hours (if my old memory is correct) wow! 18 bucks each! I traded for a 115EFI Merc four stroker and it's ok and quieter than the Opti in all but near full throttle where it is fully as noisy as the opti. I miss the performance of the Opti but not the noisy idle and cruise speed. Happy Whalin'... Clark... Spruce Creek Navy
TRAFFICLAWYER posted 12-07-2006 09:34 AM ET (US)
"jimh posted 12-07-2006 01:12 AM ET (US)
--------------------------------------------------------------------------------
A Mercury mechanic (that I judged to be quite earnest and experienced) told me that he liked the 2.5-liter OptiMax engines because of their excellent record of few problems with power head failures."
He forgot about mine. For the short duration of it's life [x2] it sounded like a Toro/Snapper on the transom. [oops actually my Snapper is quieter]
jimh posted 12-07-2006 02:15 PM ET (US)
Many years ago as a new home owner I cut my own lawn and took great pride in my TORO lawn mower. It ran quite nicely and gave great service (until it was stolen). I mention this because I don't know if making a comparison of an OptiMax to a TORO is supposed to be a compliment or a criticism. For me, "runs like a TORO" is praise.
TRAFFICLAWYER posted 12-07-2006 05:12 PM ET (US)
Correcto-Mundo, the Toro I had ran great also but alas time and hours took it's toll. When I ran the Toro I wore ear muffs due to the amplitude of the motors NOISE, I didn't get a chance to purchase ear protection when I had the 135 Opti since It detonated relatively early in its life span compared to the Toro.
For me " Sounds like a Toro" is critisism.
jimh posted 12-07-2006 08:17 PM ET (US)
Also, I would not have any qualms about getting a model-year 2000 Optimax 135-HP. Even though Mercury re-introduced the OptiMax motors this fall as the "Optimax The Next Generation" or the "Gen-Two Optimax' motor, it appears they did not change a thing on the 2.5-liter engines. The newest GEN-TWO motors appear to be about the same as this c.2000 motor, other than a new decal on the cowling.
sosmerc posted 12-07-2006 11:49 PM ET (US)
Mercury has made MANY changes to the Optimax motors since their introduction....too numerous to mention here. From my experience, 2003 was the model year where the 2.5 Optimax engines really hit their stride and became more or less trouble-free. From here on out I think most of the changes are going to focus around changing their sound quality and further improving their software for easier troubleshooting and fault code diagnosis...more user friendly.
The 1.5 litre 3 cylinder Optimax motors were released in model year 2004 and had the benefit of knowledge gained from previous V-6 Optimax models. They are very quiet and smooth and have been virtually trouble-free.
I look forward to the "Next Generation" 2.5 and 3.0 litre Optimax engines because, if they are anywhere near as quiet and smooth as the 75/90/115 Optimax engines they are going to be more impressive than ever.
And in the near future, I'd sure like to see a 4 cylinder Optimax to fill in the 125/135/150 niche using a similar size and layout to the previous 2 stroke L4.
mtwilling posted 01-30-2011 10:10 PM ET (US)
This older thread on the Optimax is helpful. I recently sold my 16 Dauntless with a four stroke and now have my eye on a pristine 2004 180 Dauntless with an '04 Merc 150 Optimax with 175 hours. I have not yet been able to run the boat and my only hesitation in buying it is the lack of a four stroke. Is the noise level of this era Opti 150 as loud as some of what is described here?
I had a '98 135 Opti on a Mako and it was flawless, but noisy. I am not at all concerned about reliability, just noise level.
Thanks
jimh posted 01-31-2011 08:59 AM ET (US)
I do not believe that the 2004 Mercury 150-HP OptiMax will have any significant improvement in sound characteristics compared to a 1998 motor. This is based on the precise words of Mercury used in making the announcement of the OptiMax The Next Generation motors
The best summary of all the changes which occur between an original OptiMax engine and the newer OptiMax The Next Generation (OTNG) engine is presented in an article I wrote five years ago. See
OTNG--OptiMax The Next Generation
http://continuouswave.com/ubb/Forum1/HTML/011847.html
I do not believe that a 2004 engine will fall into the epoch of the new design. As with many Mercury motors, the easiest way to recognize the design epoch of your motor is by the adornments used on the cowling. If your engine cowling has the "OptiMax globe" adornment, it will be of the newer design. Other than these cowling design changes, Mercury does not otherwise make a distinction in model name of the engine.
When Mercury announced that it was introducing new models of their OptiMax engine it referred to the new engines as OptiMax The Next Generation (OTNG). With regard to noise the OTNG engine in certain models were to have an improvement in noise or "up to 6-dB."
As a measurement of change in sound level, a change of 6-dB is certainly a noticeable change, but it is not a dramatic change. Perhaps recognizing this, Mercury began to alter its presentation of the change in sound level by using extraordinarily unusual measurement terms, such as percentages. In the history of sound measurement, no one has ever used percentages to make comparisons in sound levels, as the range of human hearing and sound perception is very much greater than the range usually expressed by percentages. Use of percentages is very likely to over state any sound level change and to mislead customers into thinking the change was more significant that it actually was.
When Mercury said that the improvement in the OTNG motors would be "up to 6-dB" they left themselves a lot of wiggle room. Between no change and a change of 6-dB is a huge range for actual result to fall into. They also stated that this change in sound would occur only in the models based on the 3-liter engine.
dgoodhue posted 01-31-2011 09:12 AM ET (US)
FYI 6db quieter is about 1/4 the energy of original sound. From a human ears stand point, -10db is what many would perceive as half as loud.
mtwilling posted 01-31-2011 07:55 PM ET (US)
Jim, this is very helpful. Looks like I need to go take a test drive and hear how it sounds. I hope I like it.
Gene
sosmerc posted 02-04-2011 08:09 PM ET (US)
I have found that alot of what you hear depends upon the hull and boat design.....as well as specific atmospheric conditions. But having said that, 2 strokes are always going to be at least slightly noisier than 4 strokes. In some cases, if the engine is "too" quiet....you begin to hear other potentially annoying sounds that you previously may not have been aware of :)
mtwilling posted 02-04-2011 10:29 PM ET (US)
Good point. I am hopeful that the design of the flip up stern seat on the Dauntless will act to deflect some of the engine noise when running. It looks like it will.
boatdryver posted 02-05-2011 11:12 AM ET (US)
I think what sosmerc has just said is so very important. There's more to the perceived noise level of a given motor than just the motor itself, and its important to do a sea trial in the specific motor/boat combination one is thinking of buying, used or new,in order to make a decision on the basis of motor noise.
I took a test ride in a Boston Whaler Conquest 21 with a 1999 200 HP Optimax. This boat had a canvas top and plastic side windows. At the helm, the noise of the outboard motor was so offensive I was relieved to get off the thing.
Soon after that I was a client on a heavy welded aluminum open 22 foot open guide boat (just a huge skiff) powered by a 1999 200 HP Optimax motor with a jet drive, which means all exhaust is above the water. Seated at a similar distance from the motor at cruise, the apparent wind going past my ears at 30 mph made the noise of the same Optimax motor quite tolerable.
JimL

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Author	Topic: Mercury OptiMax Engine: Noise Signature, Smoothness
jjdiv	posted 12-06-2006 03:17 PM ET (US) I would apppreciate hearing about any experiences with a model-year 2000 Mercury OptiMax 135-HP engine with 50-hours of running time. [Give it a rating on a scale of] 1 to 10. How smoothly do [135-HP Mercury OptiMax engines] run across the RPM range? How noisy is [a 135-HP Mercury OptiMax engine] at headway speeds? Thanks!
sosmerc	posted 12-06-2006 10:49 PM ET (US) If you compare a 2000 135 Optimax to just about ANY of the newer engines, whether 2 stroke or 4 stroke, you are going to find it is rather noisey. I work on Mercs for a living (for over25 years) and I am a die-hard Merc fan...AND I own a 1998 135 Optimax...BUT, I do not like the sound of ANY of the 2.5 litre Optimax engines. Merc knows they have a problem and I hear they are working on it and will soon introduce quieter models. But that doesn't help you or me. The Optimax 135 is a strong performer as far as power and efficiency. The sound quality at idle is ok, and even at WOT, though loud, it isn't unpleasant. But at Mid-range there is a particular resonance that I find offensive and others have commented as well. The 1.5 litre and 3.0 litre models are different and I don't mind them at all. In fact, the 3 cylinder 1.5 litre Optimax engines appear to be just as quiet as the new 115 4 stroke Merc. If you are contemplating buying a used boat with an older Optimax 135, you need to go for a ride and judge for yourself whether or not you would want to cruise for an hour with that noise behind you.
sosmerc	posted 12-07-2006 12:08 AM ET (US) Some noise comparison taken from Whaler provided performance data: 135 Optimax at 600 rpm.........82 dB(A) 115 Merc 4 stroke @ 600 rpm....59 dB(A) 135 Optimax at 3000 rpm.......102 dB(A) 115 Merc 4 stroke @ 3000 rpm..91 dB(A) 135 Optimax at 5500 rpm.......105 dB(A) 115 Merc 4 stroke @ 6100 rpm..101 dB(A) BUT...the 135 Optimax got a 3469 lb. Ventura to 30mph in 5.8 seconds While it took the 115 4 Stroke 10 seconds to get a 2967 lb Montauk to 30 mph. So as you can see, there is always some give and take. If Mercury can get the larger Optimax engines into the 4 stroke "quiet zone" they will really have something to brag about!!
jimh	posted 12-07-2006 01:12 AM ET (US) A Mercury mechanic (that I judged to be quite earnest and experienced) told me that he liked the 2.5-liter OptiMax engines because of their excellent record of few problems with power head failures. The larger displacement, 3.0-liter OptiMax engines have been more problematic, and this has given the whole OptiMax engine line a bit of baggage to carry around. The 135-HP engine is the mild tuning version; this same engine can produce up to 175-HP as an OptiMax, and much more as a race-tuned motor. The OptiMax motors have been tested recently and have shown best-in-class performance in terms of power and fuel economy. The older OptiMax motors were designed and manufactured at a time when noise, vibration, and harshness (NVH) were not as prominent in the buyer's selection criteria as they are now, and, as a result, these motors are not as quiet as many current designs. If noise is an important criterion, you must give this engine a careful listen to see if it will be acceptable to you. As with any used mechanical device, the condition is of paramount concern. This will have the biggest influence on a decision to buy or not. It is also often recommended that the engine's history be checked with the manufacturer to verify if there were any field service bulletins, upgrades, recalls, engineering changes, etc., that were issued for the motor and whether or not they were performed on this particular motor. A cooperative Mercury dealer should be able to assist you with that inquiry.
Clark Roberts	posted 12-07-2006 08:53 AM ET (US) I agree with the above responses and will add my experience with my 2000 Opti 135. I put over 500 hours on it on a 1979 Revenge 21 and it performed flawlessly and only time in shop was for a fuel injector upgrade. It felt like a 175hp with a savage hole shot and it would run 46mph at full throttle and got 5.5mpg at a 30 mph cruise. My complaints (other than the noise as mentioned above) was a hot idle. At idle it would run hot enough to set off the overheat buzzer on occasion. I replaced the factory 143degree thermostats with 120 degree (not recommended since the colder idle creates more polution I'm told) and problem solved. Later I put the 143's back in cut a loop off the poppet balve spring so that it opened with less press...again problem solved. I put in new plugs at about 200 hours (if my old memory is correct) wow! 18 bucks each! I traded for a 115EFI Merc four stroker and it's ok and quieter than the Opti in all but near full throttle where it is fully as noisy as the opti. I miss the performance of the Opti but not the noisy idle and cruise speed. Happy Whalin'... Clark... Spruce Creek Navy
TRAFFICLAWYER	posted 12-07-2006 09:34 AM ET (US) "jimh posted 12-07-2006 01:12 AM ET (US) -------------------------------------------------------------------------------- A Mercury mechanic (that I judged to be quite earnest and experienced) told me that he liked the 2.5-liter OptiMax engines because of their excellent record of few problems with power head failures." He forgot about mine. For the short duration of it's life [x2] it sounded like a Toro/Snapper on the transom. [oops actually my Snapper is quieter]
jimh	posted 12-07-2006 02:15 PM ET (US) Many years ago as a new home owner I cut my own lawn and took great pride in my TORO lawn mower. It ran quite nicely and gave great service (until it was stolen). I mention this because I don't know if making a comparison of an OptiMax to a TORO is supposed to be a compliment or a criticism. For me, "runs like a TORO" is praise.
TRAFFICLAWYER	posted 12-07-2006 05:12 PM ET (US) Correcto-Mundo, the Toro I had ran great also but alas time and hours took it's toll. When I ran the Toro I wore ear muffs due to the amplitude of the motors NOISE, I didn't get a chance to purchase ear protection when I had the 135 Opti since It detonated relatively early in its life span compared to the Toro. For me " Sounds like a Toro" is critisism.
jimh	posted 12-07-2006 08:17 PM ET (US) Also, I would not have any qualms about getting a model-year 2000 Optimax 135-HP. Even though Mercury re-introduced the OptiMax motors this fall as the "Optimax The Next Generation" or the "Gen-Two Optimax' motor, it appears they did not change a thing on the 2.5-liter engines. The newest GEN-TWO motors appear to be about the same as this c.2000 motor, other than a new decal on the cowling.
sosmerc	posted 12-07-2006 11:49 PM ET (US) Mercury has made MANY changes to the Optimax motors since their introduction....too numerous to mention here. From my experience, 2003 was the model year where the 2.5 Optimax engines really hit their stride and became more or less trouble-free. From here on out I think most of the changes are going to focus around changing their sound quality and further improving their software for easier troubleshooting and fault code diagnosis...more user friendly. The 1.5 litre 3 cylinder Optimax motors were released in model year 2004 and had the benefit of knowledge gained from previous V-6 Optimax models. They are very quiet and smooth and have been virtually trouble-free. I look forward to the "Next Generation" 2.5 and 3.0 litre Optimax engines because, if they are anywhere near as quiet and smooth as the 75/90/115 Optimax engines they are going to be more impressive than ever. And in the near future, I'd sure like to see a 4 cylinder Optimax to fill in the 125/135/150 niche using a similar size and layout to the previous 2 stroke L4.
mtwilling	posted 01-30-2011 10:10 PM ET (US) This older thread on the Optimax is helpful. I recently sold my 16 Dauntless with a four stroke and now have my eye on a pristine 2004 180 Dauntless with an '04 Merc 150 Optimax with 175 hours. I have not yet been able to run the boat and my only hesitation in buying it is the lack of a four stroke. Is the noise level of this era Opti 150 as loud as some of what is described here? I had a '98 135 Opti on a Mako and it was flawless, but noisy. I am not at all concerned about reliability, just noise level. Thanks
jimh	posted 01-31-2011 08:59 AM ET (US) I do not believe that the 2004 Mercury 150-HP OptiMax will have any significant improvement in sound characteristics compared to a 1998 motor. This is based on the precise words of Mercury used in making the announcement of the OptiMax The Next Generation motors The best summary of all the changes which occur between an original OptiMax engine and the newer OptiMax The Next Generation (OTNG) engine is presented in an article I wrote five years ago. See OTNG--OptiMax The Next Generation http://continuouswave.com/ubb/Forum1/HTML/011847.html I do not believe that a 2004 engine will fall into the epoch of the new design. As with many Mercury motors, the easiest way to recognize the design epoch of your motor is by the adornments used on the cowling. If your engine cowling has the "OptiMax globe" adornment, it will be of the newer design. Other than these cowling design changes, Mercury does not otherwise make a distinction in model name of the engine. When Mercury announced that it was introducing new models of their OptiMax engine it referred to the new engines as OptiMax The Next Generation (OTNG). With regard to noise the OTNG engine in certain models were to have an improvement in noise or "up to 6-dB." As a measurement of change in sound level, a change of 6-dB is certainly a noticeable change, but it is not a dramatic change. Perhaps recognizing this, Mercury began to alter its presentation of the change in sound level by using extraordinarily unusual measurement terms, such as percentages. In the history of sound measurement, no one has ever used percentages to make comparisons in sound levels, as the range of human hearing and sound perception is very much greater than the range usually expressed by percentages. Use of percentages is very likely to over state any sound level change and to mislead customers into thinking the change was more significant that it actually was. When Mercury said that the improvement in the OTNG motors would be "up to 6-dB" they left themselves a lot of wiggle room. Between no change and a change of 6-dB is a huge range for actual result to fall into. They also stated that this change in sound would occur only in the models based on the 3-liter engine.
dgoodhue	posted 01-31-2011 09:12 AM ET (US) FYI 6db quieter is about 1/4 the energy of original sound. From a human ears stand point, -10db is what many would perceive as half as loud.
mtwilling	posted 01-31-2011 07:55 PM ET (US) Jim, this is very helpful. Looks like I need to go take a test drive and hear how it sounds. I hope I like it. Gene
sosmerc	posted 02-04-2011 08:09 PM ET (US) I have found that alot of what you hear depends upon the hull and boat design.....as well as specific atmospheric conditions. But having said that, 2 strokes are always going to be at least slightly noisier than 4 strokes. In some cases, if the engine is "too" quiet....you begin to hear other potentially annoying sounds that you previously may not have been aware of :)
mtwilling	posted 02-04-2011 10:29 PM ET (US) Good point. I am hopeful that the design of the flip up stern seat on the Dauntless will act to deflect some of the engine noise when running. It looks like it will.
boatdryver	posted 02-05-2011 11:12 AM ET (US) I think what sosmerc has just said is so very important. There's more to the perceived noise level of a given motor than just the motor itself, and its important to do a sea trial in the specific motor/boat combination one is thinking of buying, used or new,in order to make a decision on the basis of motor noise. I took a test ride in a Boston Whaler Conquest 21 with a 1999 200 HP Optimax. This boat had a canvas top and plastic side windows. At the helm, the noise of the outboard motor was so offensive I was relieved to get off the thing. Soon after that I was a client on a heavy welded aluminum open 22 foot open guide boat (just a huge skiff) powered by a 1999 200 HP Optimax motor with a jet drive, which means all exhaust is above the water. Seated at a similar distance from the motor at cruise, the apparent wind going past my ears at 30 mph made the noise of the same Optimax motor quite tolerable. JimL