posted 05-20-2009 08:04 PM ET (US)        

I dug around back in 2006 and the web info at the time seemed to indicate cylinder seizures were mostly on #6. I was pretty determined to switch to the Verados but Merc 2nd line management at corporate assured me the #6 cylinder issue had been addressed and was not present in the 2006 units.

Well, here I am to say otherwise. The odds of randomly blowing two of the exact same cylinders are 1/6 times 1/6 or 1 of 36. Unless there is an inherent engineering issue where that cylinder is less robust than it's sisters.

So, just like in 2006 I dug around some more this week. I found some more guys here and there talking about their engine's seized piston being #6. I am very nervous now about the Starboard unit. I would not mind it if the engines started to "fail gracefully" such as burning more oil, smoking a little, etc. Nothing lasts forever. But this tendency to just self destruct with no advance warning or telltale symptoms is disturbing to me.

And the kicker for me - I am very frustrated indeed - this is the FOURTH time the boat is being repowered and it is only the start of the 7th season. The last two years were trouble free. But looking at my records, and the dealers says it will be about another 10 days before I get the boat back this time - I lost an average of about 3 weeks per year during the prime summer season each year with my boat out of the water over the last 7 seasons. Here in the Northeast in upstate NY where the season is really 10 weeks of warm weather that is an average of a 30% hit.

I love my Conquest's hull but have become totally frustrated at the poor reliability of the black things on it's transom as I seem to loose a 3rd of each summer towing the boat back and forth to the dealer. About 90% of the hours on the engines are trolling for Kings on Ontario at 800 RPM or less. I rarely bring the engines up to WOT. I tend to cruise around 4300 to 4600 rpm. She stays wintered in my heated garage. I run QuicKleen, stabilze the fuel for winter down time and in general baby them. I put in 12 new spark plugs about 20 hours before this fail and all of the old plugs I took out looked great. I never cold work the engine by jumping her on plane right after a cold start. These Optimax troll all day with no smoking or complaints and jump right up on plane with no hesitation even after 6 or 8 hours of trolling. So I am very impressed from that perspective. I just wish they didn't blow up out of the blue!!

Has anyone else on this site been through this cylinder #6 issue on these 2005/2006 200 HP Optimax? Does anyone know of any confirmed reason/action taken by Merc to address this since the 2005/2006 model years?

I know there are many theories about why an END cylinder might be more or less prone to this, but I am looking for FACTS in regards to this specific situation.

Any such info would be appreciated.

posted 05-21-2009 09:28 AM ET (US)            

I suspect #6 cylinder has a systematic issue by design which tends to make it a little more vulnerable than the others (say it draws air through the intake a little more readily because it is at the end of the plenum which would make it tend to run a little leaner in general than the others) and then, under some set of circumstances, "something else" comes along that has a tendency to remove the film of lubrication on the cylinder wall(s) (too much fuel washes it away, timing a little too advanced for a few seconds - you name it), perhaps to all 6 cylinders, and #6 is just the one closest to the edge of loosing that lubrication in the first place so she tends to go first.

I kid you not. I found one dealer's blog in Florida when I started this research in 2006 after my first #6 cylinder froze who complained he had swapped out 28 powerheads on the 2004 and 2005 years during the summer of 2006 and all 28 were #6. Sure, you hear it on the internet and know to be careful of such anecdotal stories. But here I am with my very own 2nd #6 fail. The odds of throwing the port engine vs the starboard, given all else is equal, is 1/2 times 1/2 or a 1 out of 4 chance. I am not convinced on that number that there is "something going on" with the Port position vs the Starboard. However, with 1 out of 36 odds on the 2 consecutive #6 fails, I am 97% sure #6 happens to be the weak link to whatever is going on. I have no idea if it is a systematic issue (say bad gas or bad operation by me) making life bad for all 6 cylinders and #6 is just more vulnerable by a little bit or if there is something unique to the design that makes #6 lots more exposed to the issue.

I am just hoping to find some real facts as to the mechanism of this specific issue so I can try and avoid these "out of the blue with no warning" fails.

Regards to all,

ROCKET

posted 05-21-2009 10:40 AM ET (US)         

With that, I'm not sure how it would help you predict future failure without either changing engine brands or utilizing Mercury's other offerings. I have not heard anything like this with regard to the Verado. Having spent some time on friends' boats with Verados, you would probably be very pleased with the change. They are very quiet, smooth and powerful. Of course, Verados are expensive, so I'm not sure of how you would "encourage" Mercury to make the change and keep it cost effective to you.

posted 05-21-2009 01:46 PM ET (US)            

Look, I do not want to turn this into a "bash Merc" post or a debate on various engine types or even Merc as a company vs Yamaha/Suzuki etc. I am just looking for hard facts on this #6 cylinder issue so I can make some decisions.

How do I check Merc Service Bulletins? I thought they were restricted to the dealers. If there is public access I would certainly like to go through them. Just tell me how to access them.

I am still hoping someone on this site who happens to have an inside track and access to the real facts might provide some concrete input about ECs or Merc activity concerning the cylinder #6 issue on these 3.0 liter blocks. I asked Merc 2nd line direct last time and all they would say is action was taken to address the rash of 2004/2005 cylinder #6 fails and that the 2006 were not expected to have the problem anymore based upon those ECs. For example, have they taken any additional Eng action about the issue since 2006?

If I knew what the root cause was thought to be and what the attempted corrective actions were, and if any additional action were done since 2006, I could then feel more comfortable about staying with the Optimax 3.0 liter block or not.

posted 05-21-2009 02:26 PM ET (US)         

http://www.marinepartsman.com/mercury-marine-engine-service-bulletins. html

http://www.marine-maintenance.com/webpages/servicebulletin.html

http://www.boatamerica.org/recall/archive.htm

posted 05-21-2009 11:52 PM ET (US)            

I note that during the 1st 20 hours of break in on a new power head the computer runs TWICE the oil relstive to what it runs after break in is completed. I do not recall any fouling or smoking issue breaking in the two new engines in 2006. So, it seems the system can tolerate the higher oil but maybe the EPA emissions would go down hill and Merc certainly could not be expected to recommend that in writing. Illegal. So, I put it to the gang. Is there any harm in doping the oil to 100 to 1 or so to mitigate the risk of future piston seizures? Could this somehow make matters worse? I figure ask before leaping!

posted 05-22-2009 10:48 AM ET (US)            

1)Have new powerheads installed and sell the engines with warranties, should get good money then.

2)Run the engines and buy another boat for backup when these fail an then you won't be sitting on land. Who only has 1 boat anyway???

3) Get some friends who have boats and mooch for once off them instead of vice versa.

posted 05-22-2009 11:39 PM ET (US)            

The piston wall was scored on the 2005. Rings were kind of welded into the piston. Not sue yet on the current fail. One other guy who chimed in last time had the same exact scenario as my 2005 fail with his 2003 unit. He was trolling for quite some time, picked up the lines went to put her on plane and she lost power without warning just before coming onto plane. He also had badly scored cylinder. He had 500 hours, I had 450 last time and 650 this time but I stress the ECU dump showed only about 100 hours above 1000 RPM. It is almost all trolling at 700 RPM puncutated with 15 minute runs on plane to get to and from the trolling area.

My warranty ends in 3 days! The new unit being put on under warranty has only 3 days of protection on it. The starboard side, which I am quite concerned also has the same issue possibly in it is also out of warranty in 3 days. At this point we run and see what happens. The odds are the new powerhead will last two or three seasons (unless Merc fixed the issue in which case they may last longer). If the old starboard unit dies this summer it would probably make sense to buy a new powerhead (about $6K?) and then with both units being new we are all set for 2 to 3 years. But when one of those pop 2 or 3 years out - then it is time to go Suzuki 4 strokes.

posted 05-23-2009 07:37 AM ET (US)            

Search for CW member Seahorse and send him an email requesting him to see this discussion. He may have some input.

posted 05-23-2009 12:28 PM ET (US)            

I keep looking around in my marina. A large majority of boats are in the 24 to 32 foot range (lake Ontario). About 80% run inboards, 10% I/O and 10% outboards.

So, 90% are running classic automotive style v-8s (inboards and I/Os) for power. There is a very good reason for that, eh? I increasingly see them using a 20 or 30 HP fourstroke outboard as a TROLLLING MOTOR to save them wear and tear on the main propulsion systems.

One great setup I saw were twin big block chevy Inboards with a small Yanmar Diesel (25 HP or so)driving a 3rd prop. Now THAT was a kick ass, high reliability set up in a 10 meter Trojan. The skipper told me he saves about $6K/year in fuel cost let alone the benefits of reduced hours on those big blocks. Plus the third layer of reliability should BOTH big blocks go south (say for bad fuel?) they still have ability to maneuver and make 7 or 8 mph on the small diesel.

A 22 footer across from me has an old 2 stroke 200 HP outboard. Thing is horrendous when he starts it in the mornings. Smokes fierce! Stalls 2 or 3 times until it warms up. He has to mix gas and oil and it is a real damned mess. He has to have a 2nd smaller outboard (another 4 stroke troll motor) because the 200 HP will not troll long without loading up the plugs. But we laugh every time I have to get another set of engines or miss a weekend here or there to pull the boat onto it's trailer again for service. He just keeps on enjoying his system as it is predictable and keeps on working through it's expected life cycle.

Open and closed loop systems in regards to engine reliability:

I have a 502 cubic inch Chevy in a little play toy I built for the 4x4 off road game. Check out my YOUTUBE videos. My page is 1966IH. I put a Holley 4di throttle body fuel injection system into it. It taught me a lot about open and closed loop systems and WHAT to monitor in regards to preventing catastophic failures. I will bring the point back to 2 stoke and 4 stroke marine engines, bear with me.

I chose throttle body instead of tuned port because on throttle body you can remove the air cleaner and see the injectors spray with your eyes!! On a tuned port all the injectors are atop the cylinders and their spray pattern is hidden. If you loose the proper pray pattern or an injector starts to go south on a tuned port the cylinder will most likely go lean and die in short order. You are less likely to do that on the throttle body setup. You are more likely to notice a performance issue or unusual Exhaust Gas Temp or O2 oddity BEFORE you torch a cylinder and just pulling off the air cleaner and looking at the injectors as she idles will at least give you a clue as to the fuel delivery system being OK. The Exhaust Gas Temperature and 02 sensors (if your software setup even have them) is usually only on one bank of cylinders as is the oxygen sensor. On a tuned port the one lone cylinder starting to run lean will not be detected in a sense that one could use the computer to stave off disaster. The computer will merely see the overall 02 level or EGR level changing and it will try to compensate by altering timing or fuel feed or perhaps at low RPM the amount of air through the idle air control motor servo. All to no avail in regards to preventing that one cylinder for burning up. here is a little better chance to stave off disaster with the throttle body because the injector is serving two to four cyinders. But if the sesors in the exhaust are on the OTHER bank of cylinders you are still screwed.

My point - open loop systems - of which the Optimax is one in most regards - are just accidents waiting to happen. Both 2 stroke and 4 stroke systems really need at least an 02 sensor and Exhuast Gas Temp Sensor on each bank of cylinders in v4/v6/v8 engines if we want to have a decent chance at staving off disaster when something starts to fail. Just like we used to have 1 coil serve an entire engine and eventually we migrated to a coil per cylinder - even though it went agsinst the old mantra of "less is better" or "more wires and parts is a BAD idea" - the new coil per cylinder tech is AWESOME for reliability. On the newest Big Suzuki there are no longer traditional spark plug wires. The coil is literally right in the "cap" that slides onto the top of the spark plug.

We need to get the marine outboard manufacturers of the engines used on Big Water in particular, to realize that TRUST and RELIABILITY through the expected life cycle is very critical to the customer because of the potential consequences of a hard fail 90 miles out fishing the canyon.

I would like to see closed loop systems on a PER CYLINDER basis watching the Exhaust Gas temp, 02 levels, water/cylinder wall temp, spark voltage and duration, fuel pressure being injected, oil pressure, air pressure - whatever. With today's technology for incredibly robust RTD (resistive thermal device) sensors there is little reason to NOT do it. The days of having one sensor on the fuel pressure at the main pump's output or oil pump's output for directly injected oil systems and then ASSUMING it is always delivered equally forever and ever to all of the cylinders is coming to an end! I have even seen systems that watch the CURRENT the fuel and oil pump motors use. Why? Well, if the pump starts to draw excessive current for a particular condition (which is different than simply blowing a fuse at max rate) that in itself becomes a clue that the pump motor or load that the pump motor drives is starting to have an issue. That type of thinking staves off fails before they get expensive or surprise you.

So, I do not think having a 2 cyle DFI or a 4 stroke or even a Diesel is the real issue on big water engines. We can select the appropriate engine for the appropriate job. I think having the proper sensors in the proper places so we can see trouble coming and better avoid unexpected catastrophic fails is the real issue.

In the end these engines will COST LESS!!! I know, that seems to fly in the face of logic. Listen, YOU PAY FOR WARRANTY COSTS. The manufacturer has to price the product in such a way that the revenue coming in from sales can support not only the build, R&D and advertising, but WARRANTY cost. You only get warranty cost when things break when they are not expected to. Having to replace a power head because it exploded is huge $$. By having a BAD/Unreliable product the manufacturer has to raise the price to cover the warranty claims. So, if a product is quality built and sensored in such a fashion as to stave off unexpected exploded power heads the unit cost to manufacture may go up but the warranty cost will go down. Sure, there is a balance point. I am just suggesting that we are quite a distance from it right now. The marine engine builders of "big water" engines and their customers would be much better off spending the extra effort up front with the sensing of key parameters on a per cylinder basis and so forth because then the warranty issues will become less expensive and the customers will be getting less unexpected catastrophic fails. The large drop in warranty cost will easily cover the small rise in manufacturing cost and I think leave enough left over to actually reduce the overall price making them even more competitive without impacting the profit for the manufacturer. It is a WIN-WIN. Instead of replacing a complete blown power head they will be replacing a fuel pump or an injector or maybe find an air leak into the cylinder before she blows up and I think in many cases, if the computer diagnotics are worth a darn, the maintenance guy in the shop or even the customer might be able to find and correct an issue more quickly to the direct root cause instead of throwing parts at it and hoping to eventually address it.

Whew! Comments welcomed.

ROCKET

posted 05-28-2009 01:28 PM ET (US)            

FYI - I had a 3 way hour discussion yesterday with Corporate 1st and 2d line Customer Service Managers concerning my current blown power head. They have agreed to have their guys at the factory tear it down and try to establish root cause. Specifically, they agreed to let me know how all 6 cylinders look as well as anything they see which leads them to believe one thing or another. I am OK with that. I was asking them to allow me to do it but said I do trust them and would feel better about a "real motor head" opening it up for analysis than me opening it up.

I will let you know what they conclude.

Thanks again for this input.

ROCKET

posted 11-21-2009 09:51 PM ET (US)            

Any responce from Mercury on the tear down of your blown engine? Did they just blow you off?

I like the idea of the additional oil in the fuel, I understand that it will only lube the cylinders and not the crank or connecting rods but hey that's not what destroyed your engine.

Hope you got to use your boat instead of looking at it sit on a cradle like I did with my Conquest this summer.

posted 11-22-2009 07:07 PM ET (US)            

I have twin 1999 Merc OptiMax 225's on my 280 Conquest.

My OptiMax are oil and fuel injected seperately. The oil is injected into the crankcase along with the combustion air. The fuel is injected directly into the cylinders. If I were to add oil to my fuel the only additional protection I would get would be my cylinders.

If my oil injection were to fail, the crankshaft main bearings, connecting rod bearings on both the crank end and the wrist pin end would be starved for oil and destroyed.

To add 2 cycle oil to 298 gallons of fuel would I think be a waste of money. My only added protection would be to the pistons, rings and cylinder walls.

Without the oil injection operating properly the engine would continue to run until the bearings melted from the heat. So I guess I'd have another Mercury "OptiAnchor".