Twin Merc. 6.2 Mags with Bravo 3 - EMCT Temperature Overheat Fault - Port side Manifolds (Only)

[Ploring]

You should have PMed me. I removed my cats years ago since the post O2 sensors kept failing after about a year (max volt cat simulator). You post cat O2 sensors are bad (obvious in picture), Wagner makes a replacement for the quicksilver/mercuriser O2 for about 60% of the price $55. When you removed the O2 sensors to replace elbows you torqued them, they rust and expanded again elbow and then when you unscrewed that busted the POS. Usually I recommend quicksilver but for an O2 sensor who cares. Pre Cat o2 sensors never seam to fail. With the new elbows your temp problem should go away. My manifolds were perfect same age as yours. In the elbows its the air to water interface that expedite corrosion.

The max volt cat simulator $460 works flawlessly and after 100? plus hours never a code for o2 sensor again. I love the smell of exhaust vs skunk also. My pinging with 87 octane also disappeared with removing the Cats generating 1200F heat. On my 100 plus mile trip Saturday my EMCT was 138F-140F is that cool enough??? I imagine my new elbows will be lifetime since my manifold temps are so much COOOOOOOOLER without the furnace fking cats. There you go, you want cooler EMT simple remove cats......

I looked at retrofitting old style manifolds but I glad I didn't, the new cat manifolds are very smooth, no square edges or corners for sentiment to build. Most old style manifold failures I seen is the result of sediment causing the manifold to overheat and crack. I sure you have the multi-drain system. A couple times a year when flushing open it up and let water go into bilge during flushing. This purges any sediment and makes sure all your check balls are clean in case you drain for winter.

Throw your old cats in attic if you remove. You can probably get $1K each for them. I believe they are $2400 new each, and that my friends is what killed the sterndrive engine and why we see outboards on everything until they require cats are those......

The POS cats are very fragile, you run rich you fk them, you shut engine off after hard runs without cooling the engine down (think run aground) you hurt them, all the alarms you have now, I think 41 vs 3 are to protect the fragile Cats. How much environmental damage was done making the cats? making o2 sensors that fail? for boats that see 500 hours in 10-15 years....

Your PCM is not a PCM 555 that is for not cat engine. I believe your is PCM 009 but I have to look at my manual which I don't have right now. You could always retrofit to a PCM 555 with new wiring harness and knock sensors but once you get past the cats your engines are reliable.

Thanks for your reply. Just Pm’d

 

[tpenfield]

CATs or No CATS the exhaust on those engines is expensive, since they are Mercruiser's design and not available from aftermarket providers (yet?) You are probably getting close to when the exhaust will need replacement in general.

 

[Ploring]

CATs or No CATS the exhaust on those engines is expensive, since they are Mercruiser's design and not available from aftermarket providers (yet?) You are probably getting close to when the exhaust will need replacement in general.

 

[Ploring]

I tend to agree with that logic. Interesting though My local merc parts guy said that he’s seeing the risers wear out about now on my engine age but not the manifolds. He said the dry joints are definitely lasting a lot longer

 

[tpenfield]

I tend to agree with that logic. Interesting though My local merc parts guy said that he’s seeing the risers wear out about now on my engine age but not the manifolds. He said the dry joints are definitely lasting a lot longer

Not sure why you are calling these 'dry joint', since the the exhaust and water chambers are separated by a single gasket, just like the old style wet joint manifold/riser.



The old style 'dry joint' was such that if the water leaked, it would be on the outside on the manifold..

 

[Ploring]

Not sure why you are calling these 'dry joint', since the the exhaust and water chambers are separated by a single gasket, just like the old style wet joint manifold/riser.

View attachment 367035

The old style 'dry joint' was such that if the water leaked, it would be on the outside on the manifold..

I could be wrong about the name. I have heard them called that but didn’t know why. I do see a nice groove in the manifold that seems to drain potential gasket leaks away. The joint is also vertical vs the old style from my 7.4 where the riser sat on top (horizontal joint). Seems like a better design. Anyway I am happy to be corrected

 

[Searay205]

Just to document this here in case someone else needs it "My experience with clearing codes is you have to clear the codes AND go into history and clear history!!!! Both places. That will clear the codes, if you just clear codes in codes it shows clear but if you disconnect and reconnect the codes are still there until you clear history then they are gone."

As far as the 69lb manifolds they are lifetime if not plugged and if plugged you can hydro-blast them. These aren't the old manifolds of yesteryear and they have an epdm coating. Catalyst should last life of engine. Exhaust elbows do foul as we have exhaust gas, water/seawater, air all combining which is about the worst environment on planet. Even with closed cool system the Exhaust elbows corrode. Good thing is they dont corrode to the engine combustion side, they just foul and when you start getting high temps replace or clean.

the exhaust elbows are dry joint, the water passage sealing surface has a gap between it and the combustion passage. Its obvious on the exhaust elbow. Not on gasket

 

[Lou C]

Interesting read on owning a modern stern drive or inboard. As far as removing cats what is the legal liability for this? The biggest problem we have is that people running the EPA are not elected and there are no cost benefit analyses being done to justify forcing the manufacturers to install these systems and the owners get the bill for the headaches. How is it then that outboards get a pass?!

 

[Ploring]

Just to document this here in case someone else needs it "My experience with clearing codes is you have to clear the codes AND go into history and clear history!!!! Both places. That will clear the codes, if you just clear codes in codes it shows clear but if you disconnect and reconnect the codes are still there until you clear history then they are gone."

As far as the 69lb manifolds they are lifetime if not plugged and if plugged you can hydro-blast them. These aren't the old manifolds of yesteryear and they have an epdm coating. Catalyst should last life of engine. Exhaust elbows do foul as we have exhaust gas, water/seawater, air all combining which is about the worst environment on planet. Even with closed cool system the Exhaust elbows corrode. Good thing is they dont corrode to the engine combustion side, they just foul and when you start getting high temps replace or clean.

the exhaust elbows are dry joint, the water passage sealing surface has a gap between it and the combustion passage. Its obvious on the exhaust elbow. Not on gasket

Very helpful! I will clear and then clear the history too. I am pretty sure I know how to find that on the Techmate (Rinda). Still learning but definitely feeling more confident!

 

[Ploring]

So that everyone knows - currently the CATS are selling for >$2900 each. A pair of risers was a little over $1700. I probably need 4 risers but started with the 2 that were hot at the manifolds. I only had an error out of 1 of my 4 CATS so I'm feeling like I would only need to replace 1 of them to be "clean living". That one has been bad since I bought the boat - Service Engine Soon is on the dash display for this reason. I should have figured this out before buying but live and learn. I like the idea of eliminating the Post CAT Sensors A LOT because once they are in for more than a year they are basically rotted into the riser.

 

[tpenfield]

The new manifolds are a better design, it seems, but the water passages to the riser portion do not seem all that large (to me). I wonder if there is some restriction by design, since I believe the risers also get a raw water feed.

As for the faults and codes. I have the Diacom computer software . . . which has already been helpful. Yes, clear the active and inactive codes. any active ones will re-appear.

As for the sensors and exhaust . . . the sensor shown in the picture looked like it had seen better days.

As for fuse locations . . . not sure you posted your serial number, but the should be up on top of the engine and may look more like a connector than a fuse block. It seems that Merc. is doing a better job at labeling things. My engines have a clearly marked place for most/all the engine sensor fuses, but the layout of your engine looks different than mine.

 

[alldodge]

Might try some O2 extenders to get them farther away from moisture
https://www.walmart.com/c/kp/o2-sensor-extender

 

[Searay205]

get on Parts VU for the elbows, I replaced manifolds and elbows for $1700 total (pre covid) Pull your elbows off, clean gasket surface, get pressure washer and blast passages (take out allen head plugs to really blast it). Unless the end of yours broke off you can clean and reuse. In the old days the risk was the water passage corroding through to the gas side and getting water in the engine via the exhaust valves. These new manifold are so thick that will not happen and have a coating to boot. they just plug with the 1100f boiling the minerals out of the water from the cats.

 

[Searay205]

Interesting read on owning a modern stern drive or inboard. As far as removing cats what is the legal liability for this? The biggest problem we have is that people running the EPA are not elected and there are no cost benefit analyses being done to justify forcing the manufacturers to install these systems and the owners get the bill for the headaches. How is it then that outboards get a pass?!

Rumor is all PWC and Outboards and any marine engine will have Cats by 2026. Zero liability for removing cats. There no enforcing entity, no jurisdiction. Remove Cats put old O2 sensors where they are supposed to go in elbows take long leads and tie them deep under the manifold, looks like there plugged in. The simulator is small box looks like an ignition rectifier. No chance anyone would ever know. Scan the PCM no codes......

CA started in 2008 rest of country 2012. If you order a new boat make salesman check box for export (like boat sold and going to mexico). When it arrives there will not be any cats and it will have the PCM555.

 

[Searay205]

I have been looking for a 2006? Searay 205 with a failed engine (freezing etc) that I could pick up "cheap" I would then turn around and install a 350 carb engine and have the best of every world, brutally simple, brutally fast, fairly inexpensive. That said my buddies volvo froze and by the time he was done he had $6K into the engine and manifolds. So maybe not as cheap as I think lol. Again the new engines are reliable just some stupid vulnerabilities that can be eliminated.

 

[tpenfield]

Never mind the CATs - I’m more concerned about the digital throttles, electronic steering, and multitude of senders to check everything.

I’m afraid I’ll get a fault code if I bring the wrong brand of beer on board .

 

[Lou C]

Better hope that none of the states get the bright idea of emissions equipment inspections on boats after a certain year. In NY your vehicle must have all of it in place & no check engine light to pass. No sniffer test but if you’re getting any CE codes no pass. If that comes to pass then lots a luck.
All of this makes me feel I did the right thing by sticking with ancient tech. Really ALL THAT complex tech & potential expense & headaches for something you use at best 4-6 months out of the year & approx 50 hrs of run time. I can’t come close to justifying it. It’s easier to justify paying a good ‘glass shop to restore a desirable older boat!

 

[Searay205]

Better hope that none of the states get the bright idea of emissions equipment inspections on boats after a certain year. In NY your vehicle must have all of it in place & no check engine light to pass. No sniffer test but if you’re getting any CE codes no pass. If that comes to pass then lots a luck.
All of this makes me feel I did the right thing by sticking with ancient tech. Really ALL THAT complex tech & potential expense & headaches for something you use at best 4-6 months out of the year & approx 50 hrs of run time. I can’t come close to justifying it. It’s easier to justify paying a good ‘glass shop to restore a desirable older boat!

Your will die out like me one day and the world will be a better place, lol. Most people under 35 don't even know what a carburetor is, under 45 points and condenser. They will be held hostage to what is sold new as they have zero chance to keep anything running themselves. They are prisoners of the repair shops and service man schedules. Maybe its a better life that way but I don't think so......

 

[Lou C]

the old tech won’t die out
Just look at the classic car hobby
The nay sayers said 30 years ago carbs would disappear
Go take a look at Holley’s website, how many different types of carbs are sold currently…it’s a LOT….
Everything from 2 bbls to twin 4 bbls and 3 deuces…
I can get ANY part I need for a Quadrajet that hasn’t been built in 30 years….
From Cliffs & Quadrajet parts.com

 

[Ploring]

Okay with some great advice from @Searay205 I am starting to understand these faults. I picked up the service manual #51 tonight. I finally get it that the Post Cat O2 sensors do nothing to adjust the fuel mix. He said it 20x and by the 20th it registered . Using my Rinda I plan to clear the faults AND the history for port #354 and starboard #355. So long as the fuses are good they should be gone. I also found where the fuses using the manual. Port side of engine- on top towards the back beside the PCM - “Two 10 amp fuses protect the oxygen sensors” There is a box 5 yellow fuses. Not sure which ones yet but I will test them all if fault clear fails to wipe them.
Now - That’s not affecting my fuel mix in the starboard side cylinder bank. But maybe that’s a fuel supply issue. Or maybe one of the precat sensors is failing (without a fault). I do remember one of the sensors was throwing values that seemed inconsistent (high value variability). Or maybe it’s the distributor as per @Searay205 ?
More to follow.