CONTINUOUSWAVE

The announcement from Mercury in May 2018 that the production of OptiMax outboard engines was ending escaped my notice at that time. For many years I had been following the Mercury OptIMax engine variations, and noting changes and improvements in the product, which used the two-stroke-power-cycle method with a patented, proprietary direct-injection Orbital Combustion System, managed by highly developed engine control units. Mercury had been licensing use of the Orbital Compassion System for decades from the inventor, Orbital. The end of production of the OptiMax came when Mercury was only offering a few models of the engine, mostly those using the larger 3.0-liter V6 displacement powerhead in the 200 to 300-HP. The smaller displacement and less powerful OptiMax models had already ended production, replaced by four-stroke-power-cycle engines.

The May 2018 date was also significant because it marked the introduction of new Mercury FOURSTROKE, that is FOURSTROKE not VERADO, outboard engines in the 200 to 300-HP range

However, the OptiMax is not completely gone. Around February 2019, QUICKSILVER, another Brunswick marine brand, announced that it was introducing new products: re-manufactured 3.0-liter V6 OptiMax "fully-dressed" powerheads (that is, with all components, hoses, harnesses and so on in place) in 200 to 300-HP models. Quicksilver said that a good technician could perform the installation of a new fully-dressed powerhead onto a customer's existing midsection and gear case in about three hours. The remanufactured power heads were to be hand-build by an individual rebuilder who was highly skilled in this craft, with any original components that were out of tolerance to be replaced or remanufactured, and with all production improvements to the latest version implemented into the rebuild. The source of the blocks to be remanufactured would be the trade-in blocks from the customers buying remanufactured blocks. And in this way owners of Mercury OptiMax engines would be able to obtain a remanufactured engine to replace their OptiMax engine when the OptiMax engine in service suffered a failure that could not be easily remedied in the field at reasonable cost and time with individual replacement parts.

QUICKSILVER produced a presentation to demonstrate the remanufacturing methods and posted it to youTube in late February 2019. This presentation has been quite obscure, an inference I make because as of November 2020 the presentation had only been viewed 422-times and has received zero comments. This presentation must be one of the best kept secrets in the marine outboard engine marketplace. The presentation is nicely done and warrants more attention.

Mercury, among all outboard engine manufacturers, has had for some time a business operation of selling remanufactured engines. These engines were typically remanufactured using original production engines that had suffered significant failures while still under warranty, and which Mercury had chosen to give the customer a completely new powerhead instead or repairing the failed original power head. This business appears to be on-going, based on the publication of a 2020 product guide to remanufactured outboard and sterndrive engines.

The Mercury OptiMax is dead, but long live the Quicksilver remanufactured OptiMax 3-liter V6 power head.

Decades ago a shop under my supervision overhauled dozens of air cooled four stroke four cylinder generator engines rated at 20 HP. When we started the process we carefully measured almost every wear part to ensure it met factory specifications. Over time we learned that the wear rate for certain parts of most of the engines were usually out of specification.

To speed up the overhaul process we decided to simply replace those parts without measuring for wear. We found the time saved was enough to justify replacing some serviceable parts. Examples are piston rings and rod bearings. Measuring wear of those parts is time consuming and the parts are relatively inexpensive.

Mercury almost certainly uses the same cost cutting measures to "re-manufacture" the OptiMax engines. The best part is that overall quality is improved using the process.

Indeed, the OptiMax outboard is mostly dead. That said, Mercury is still selling the following as new:

200HP SportJet which is based on the 2.5 liter Optimax:
https://www.mercurymarine.com/en/us/eng ... et/200-hp/

175HP Diesel Outboard which is baed on the 3.0 Optimax (presumably a powerhead similar to the old Optimax:
200/225/250): https://www.mercurymarine.com/en/us/eng ... -outboard/

My 2004 Boston Whaler Nantucket 190 still has its original 2004 Mercury 135 Optimax "Saltwater" (at about 280-hours); this is a 2.5 liter version of the OptiMax. I was tentative about buying a boat with an old Mercury Optimax; however, after two seasons, I am more comfortable its reliability. That said, I am looking forward to re-powering with a modern four-stroke-power-cycle engine that makes a lot less noise.

Thanks JimH for sharing the Quicksilver video.

I’ve been fortunate with my 1999 Optimax 200-HP and there have been no powerhead problems. The biggest repair for me has been the trim-tilt hydraulics on the midsection. I will likely update to a Mercury FourStroke because of the Optimax noise level.

roundle1979 wrote:...135 Optimax "Saltwater" (at about 280-hours); this is a 2.5 liter version of the OptiMax. I was tentative about buying a boat with an old Mercury Optimax; however, after two seasons, I am more comfortable with its reliability.

The smaller displacement 2.5-liter OptiMax engines seemed to have fewer problems than the big-block engines. The Mercury 2.5-liter V6 block remains popular in outboard racing. There is a very popular class that runs the 2.5-liter Mercury block exclusively.

Mambo Minnow wrote:I will likely update to a Mercury FourStroke because of the Optimax noise level.

Engineering an outboard engine for best noise, vibration, and harshness was not a particularly high priority back when the OptiMax was first introduced. The move to direct injection in two-stroke-power-cycle engines was driven by a need to meet EPA-imposed limitations on the exhaust gas emission contents, not to make quieter engines.

An OptiMax engine has an external air compressor. The engine drove an air compressor to produce the pressurized air system that was used. As anyone who has been around a small-displacement, high-rotation-speed air compressor knows, they are not quiet in their operation. I think that contributed significantly to the noise level produced by the OptiMax.

A good article on OptiMax model changes is

OTNG--OptiMax The Next Generation
http://continuouswave.com/ubb/Forum1/HTML/011847.html

As noted in the above, Mercury prominently mentions a reduction in noise for their OTNG engines.

I decided to say goodbye to the noise and exhaust smell of my 2002 135-HP Optimax engines. My new Yamaha F150 four-stroke-power-cycle engines should be here in Jan 2021.

The OptiMax engines had 650-hours of trouble-free running and had been super-reliable.

ivansfo wrote:The OptiMax engines...had been super-reliable.

I am not sure exactly what degree of superlative quality is indicated by "super" reliable. Generally engines are reliable or not reliable. Degrees of reliability tend in imply some unreliability.

Certainly the history of the OptiMax engine was troubled by unreliability, to the point where Mercury had to shut down production for some time while they tried to figure out what was causing the OptiMax engines to fail in service. All products experience some degree of failure, so the notion of reliability is only meaningful if some data accompanies it that explains the sample size. If every OptiMax engine ever made were "super" reliable, there would not been so many warranty claims and rebuilt powerheads.