More Mercruiser 8.2L issues this winter


flyboy1

flyboy1

New member
Dealer mechanics have now replaced the 3rd and 4th exhaust flapper valves on my engines which have a total of 178 hours on them. The first two failed at 58 hours. Seems excessive to me but so far Merc has not offered any explanation for the failures and will not pay for the replacements. Anybody else having this problem?
I also had to have both gimbal bearings replaced this winter. I wasn't expecting to have to replace these this soon (178 hours). Is there such a thing as an average life for them on a 37PC?
Also dealing with a port engine "Misfire fault" that popped up at the end of last season and still needs to be addressed. The engine was not actually mis-firing and continued to run smoothly. This will have to be troubleshot with a tech at launch in May. It's been suggested to me that it might just be an oxygen sensor going bad. Any thoughts?
 
I have a 34' PC with 8.2 and changed the flappers and gimbals at 230 hrs
My dock neighbor has a 37' PC with the 8.2 HOs and he had the same code with the engine running great he took it to the mechanic he said it was a bad spark plug.
They charge him for changing a spark plug.
Code gone.
 
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Being a 8.2 with CATs, I'm thinking water flow issues. The CATs make the exhaust a bit hotter and the flow may be reduced. They use poppet valves to control the water flow. Those valves have been known to cause issues, but burning the flappers out would cause me to start checking the seawater pump and cooling system.

If your getting a misfire then there should be a code, was there one?

Don't get the gimbal bearing replacement unless there was a boot leak (My 1995 Rinker still has the same bearing). Were the drives pulled every year and checked for alignment and boot status?
 
Thanks for the reply, My spark plugs were all changed at the beginning of last season so, unless I got a bad plug, that shouldn't be the problem. Seems like your time to change flappers and gimbals made a little more sense than mine. Our previous boat was a 34PC with V-drives. That thing was bullet proof. The transition to I/O's on this boat has been anything but smooth but I do enjoy the speed capability and overall reliability has been very good.
 
I'm doing everything I can to stay away from a boat with CAT's, there is just to many folks reporting issues with them. You need a real good mechanic (Merc certified one, not one where the dealer has a nice sign on the wall) to be able to figure out what the issues are. Kind of like what Diver Girl is dealing with her diesel boat but with the VP issue's

Kind of wonder why the Mechanic has not thought or discussed the water flow possibilities. If there is plenty of water flowing across the flappers they will last a really long time
 
I have photos of the Smartcraft display when the Engine Misfire fault appeared. There is no code number displayed. My drives have been pulled and serviced each year since new. Your theory of hotter exhaust causing flapper valve damage makes sense to me although I'm not sure the issue is burning the flapper valves out rather than having their attach points physically break. I'll have to talk with my mechanic about what actually happened with them. Thanks for your insight.
 
flyboy1 said:
Thanks for the reply, My spark plugs were all changed at the beginning of last season so, unless I got a bad plug, that shouldn't be the problem. Seems like your time to change flappers and gimbals made a little more sense than mine. Our previous boat was a 34PC with V-drives. That thing was bullet proof. The transition to I/O's on this boat has been anything but smooth but I do enjoy the speed capability and overall reliability has been very good.
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Not saying this is your problem but did you ever buy anything and it was bad out of the box or went bad a week later, I think it is something to look into only because of my neighbor boat.
Its all up to you just throwing it out there.
 
flyboy1 said:
I have photos of the Smartcraft display when the Engine Misfire fault appeared. There is no code number displayed. My drives have been pulled and serviced each year since new. Your theory of hotter exhaust causing flapper valve damage makes sense to me although I'm not sure the issue is burning the flapper valves out rather than having their attach points physically break. I'll have to talk with my mechanic about what actually happened with them. Thanks for your insight.
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Just something to keep in your back pocket, but the flapper (shutter) that's used on you motor is the same ones used on my 1995 Rinker and 1994 27PC, part number 807166A1. The exhaust Y pipe is different, but doesn't look that much different

Don't have your serial number but looked through a lot of serial number ranges and part numbers has been the same
 
I had to replace my flappers that were likely burned up and crispy the day I bought the boat from PO. One side they completely fell apart and
I could see the metal pcs thru the carrier bearing slits but they were too large to pull thru. I tried unsuccessfully to fish the formerly rubber coated ss pcs out of the exhaust passages on the drive but ended up having to pull it and turn it upside down. Not kidding I inverted the lower and shook it and the pcs fell right out.
Removing the elbows and big hoses was a pita but doable. Not sure what caused the excess heat but whatever it was it got hot enough to melt the rubber coating and mounts.
Replaced all the rubber hoses also while it was apart.

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Sparkey600 said:
I have a 34' PC with 8.2 and changed the flappers and gimbals at 230 hrs
My dock neighbor has a 37' PC with the 6.2 HOs and he had the same code with the engine running great he took it to the mechanic he said it was a bad spark plug.
They charge him for changing a spark plug.
Code gone.
Click to expand...

They made a 37pc with 6.2's?
 
I'm not sure flappers last very long even under normal conditions. I replaced mine on my 7.4L MPI's and they were gone within 2 years (less than 100 hours)
 
Only replaced mine one time on the Rinker. That said I have not gone back and looked since installed a few years ago, and the ones removed where still there, just lost the rubber around the metal flapper (old style).
 
I replaced mine last year when I had the engines out of my 34pc, non cat 8.1's. I will be doing manifolds soon, and will see how they held up in 1 year.
 
Just a thought, but if there is enough room to add a riser extension, could get by without flappers
 
Wish I could say that the engine mis-fire fault (no engine issues noted) has gone away but it was back this season, twice! The dealer engine tech, who seems very competent, cleared the fault (no code that I'm aware of) a few weeks ago but the computer could find nothing wrong that might have caused it. He spent quite a bit of time physically checking for loose wires or other obvious physical problems but found none. He came back the next day to run the engine cold and still found nothing. He cleared the code and two hours of operation later it came back. At the rate I've been going through exhaust flapper valves I'm wondering if I have another failed one that may not be opening completely and is obstructing the exhaust flow enough to trigger the fault? Or, are there pieces from previous failed flappers lodged in the system somewhere causing an obstruction? If I had a bad spark plug I would think there would have been detectable signs of that. Any body have any other ideas?
 
The flappers fail by burning up, and I don't see anyway they can stick closed be their design. If they did, for sure it would have burned to bits by now. Those bits get blown out the y pipe, or sit there causing very little restriction.

There is something else wrong. Mine 1 year later looked brand new.
 
flyboy1 said:
Dealer mechanics have now replaced the 3rd and 4th exhaust flapper valves on my engines which have a total of 178 hours on them. The first two failed at 58 hours. Seems excessive to me but so far Merc has not offered any explanation for the failures and will not pay for the replacements. Anybody else having this problem?
I also had to have both gimbal bearings replaced this winter. I wasn't expecting to have to replace these this soon (178 hours). Is there such a thing as an average life for them on a 37PC?
Also dealing with a port engine "Misfire fault" that popped up at the end of last season and still needs to be addressed. The engine was not actually mis-firing and continued to run smoothly. This will have to be troubleshot with a tech at launch in May. It's been suggested to me that it might just be an oxygen sensor going bad. Any thoughts?
Click to expand...

My dock neighbor had the same code and his mechanic told him it was the coil pack and they would have to order it they said it would take six weeks to get, I said it does not sound like a coil park to me as the motor runs great all the way up to 4800 RPM, So I swiped the two coil pack to see if it would follow to the other motor.
After we drive the boat there was no change in the codes, No new codes.
He called a mercury certified mechanic and he plug a computer into the motor and it said there was a bad C02 sensor, and he change it.
a week later he gets the mis fire code again, Mechanic comes out and finds a bad spark plug wire, Changes the wire and all good.
 
Replaced my exhaust shutters 2 years ago. 100 hours later. Replaced my exhaust manifolds this Fall. One shutter was broken off and jammed in the Y pipe. It was not melted. Piece of rubber still on the metal rod. Not sure why it failed? maybe a problem with manufacturing??
 
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