Exhaust pieces and parts

[lvhdude]

I have a 1996 Four Winns 5.8L EFI with a Volvo Penta Duo-Drive outdrive. I removed both elbows behind the water cooled manifolds (working on steering issues) to find in the down pipes under the rubber bellows coupler on the down (outward) side of the cast iron elbows, there is a steel rod through the pipe, with a couple rubber washers and nothing else on them. been that way for awhile as the steel has turned the hole it went through into slots. Seems an odd place for random parts that seem to have no purpose. Can anyone enlighten me as to what might be missing? Or should be there? Maybe some sort of baffle or damper to stop a wake from washing up into the exhaust ports? I can weld and re-drill the hole for the steel rods (shafts) if need be, or just to seal them up. Thanks in advance for any advise! Joe.

 

[stresspoint]

look in the parts diagram "exhaust flappers " .
yours are broken away and remnants are probably in the bottom of the Y pipe blocking it up somewhat.

 

[Scott Danforth]

volvo long ago removed the flappers in a service bulletin.

 

[stresspoint]

volvo long ago removed the flappers in a service bulletin.

why did they remove them and leave the rods ? this is what i am interpreting the OP is concerned about .

 

[lvhdude]

look in the parts diagram "exhaust flappers " .
yours are broken away and remnants are probably in the bottom of the Y pipe blocking it up somewhat.

Parts diagram? I'm not having much luck on parts info for my 1996 boat. Any chance you have a source? Thanks.

 

[Scott Danforth]

Parts diagram? I'm not having much luck on parts info for my 1996 boat. Any chance you have a source? Thanks.

Volvopentastore

 

[Lou C]

They may come up as unavailable on the Volvo parts site because Volvo put out a service bulletin basically saying they didn’t think they were helpful & they can melt and block the exhaust if the engine overheats. So they recommended not replacing them. However the parts are still out there because OMC & Volvo had a joint venture from 1994-1998 and they adapted the Cobra drive to cone clutch shifting and slightly modified the transom mount. During that time frame the OMC Cobra & Volvo SX were identical. The original Cobra design had the flappers and I think they (OMC) kept them till the end of production (1998 for OMC) but Volvo discontinued the flappers in 97-98 I think. If you wanted to replace them the OMC parts for the same year are probably still available if you look in an OMC parts catalog for the same year power package. I have them in mine still.

All Products | iBoats

Since 1998, iboats is the most trusted water lifestyle online store for boat parts and accessories, boats for sale, and forums. Enjoy great priced products with fast shipping.

www.volvopentastore.com

OMC Stern Drive Exhaust & Cooling Parts for 1996 5.8L 58FCPNCS Stern Drive

Online inventory of OMC stern drive 58FCPNCS exhaust & cooling parts for 1996 5.8L stern drives. Buy a genuine OEM or aftermarket part.

www.marineengine.com

 

[lvhdude]

Thanks for the info. I'm fine not replacing the flappers, and it doesn't seem like there's a concern to fill the holes in the y pipe but to make sure the clamps cover them.
Exhaust seems to exit down and out through a rectangular port under the outdrive. In my Volvo Duo Drive does it also exit through the props? Debris from the flappers could be both places? Is there any obstructions at the bottom of the y pipe other than the transition into the outdrive? I'm not sure I could remove the y pipe short of pulling the engine. Shop vac with a smaller hose? Compressed air in from the exhaust port? Thoughts? Thanks for allowing me the benefit of you guy's experience.

 

[Scott Danforth]

the exhaust should exit thru the cavitation plate on VP drives

 

[Lou C]

I found my one of melted ones in the exhaust outlet in the transom mount, the other was still on the pin that fits into the Y pipe. I had to pull the drive to get access and pulled the other melted one out with a 3 jaw grabber tool. With the drive removed I was able to see it looking through the exhaust bellows. Sometimes they will be jammed into the water exhaust passage in the outdrive. Here's a pic of a melted one that hadn't dropped down, and after replacing it.

 

[Donald0039]

When did Volvo Penta stop by using the exhaust flappers all together?

 

[Lou C]

https://www.marinepartsexpress.com/VP_Service_Bulletins/158%20%20%20%20%20%20%20%20%20%20PB%20P-25-1%20%20N2%20%20%20%20V-01%20%20%20%20%20Exhaust%20pipe%20seal%20obsolete.pdf

it isn't dated but I think this happened around 1999 or so.

 

[lvhdude]

I found my one of melted ones in the exhaust outlet in the transom mount, the other was still on the pin that fits into the Y pipe. I had to pull the drive to get access and pulled the other melted one out with a 3 jaw grabber tool. With the drive removed I was able to see it looking through the exhaust bellows. Sometimes they will be jammed into the water exhaust passage in the outdrive. Here's a pic of a melted one that hadn't dropped down, and after replacing it.

I'm sure glad you guys clued me in to the flapper issue. Here's a couple pics of what I found in the exhaust port of the transom, and after an hour and quite the string of 4 letter words what I got out. Also noticed a nut missing, quality work from the shop who resealed the outdrive just before I purchased the boat.

 

[Lou C]

Good work
You can do a better job doing maintenance yourself!

 

[lvhdude]

Good work
You can do a better job doing maintenance yourself!

Sure seems to be true so long as one has the ability and the time. That is an advantage of being retired and having tools and a place to use them. I wonder if I should let the previous owner know what kind of issues I found, not that I'm unhappy with the deal, but so he might be better informed as to who services his new boat.
Thanks to all for the advice and expertise. I did find the service bulletin from Four Winns about removing the flappers, dated 2006 I think.

 

[4now04]

I experienced this with my 95 Four Winns 190 Horizon and Volvo 5.0 EFI at about 250 hours since new. With the outdrive trimmed up all the way, the exhaust bellows can be disconnected from the transom side to inspect inside the bottom end of the Y pipe. The flapper valves in my boat were rubber coated aluminum. One flapper came loose and partially blocked the exhaust in the transom area. This caused a significant power loss, and a loss of 12-15 mph top speed. We were able to fish a wire down through the y pipe and retrieve the flapper with the elbow and the bellows opened up. Some exhaust comes out under the transom shield around the transom anode at idle, but most of the exhaust goes through the prop hub at higher speeds. I also changed the anode and found a pin. The flapper installation includes the flapper, the pin, and the two rubber washers. A retrofit kit replaced the rubber washers with rubber flanged bushings.
The transom exhaust port is not as deep in the water as the prop hub, so less resistance for exhaust at idle. Hopefully, the hose between the exhaust elbow and the Y pipe can be positioned to cover the flapper pin holes or slots. You might also use tape and or silicone sealant on the holes according to the Service Bulletin. I experienced this also, but I was able to reposition the hose to stop the leak. Google "Volvo Penta flapper valve service bulletin" to find the Service Bulletin. Hope this helps.

The part that still puzzles me is Volvo/OMC using plastic parts in the exhaust system. These plastic parts and the rubber hoses are subjected to the water/exhaust, but generally are not compromised in normal use. Yet, if a plastic flapper comes loose and goes down to the bottom of the Y pipe further away from the combustion heat, many have said that the flapper melts and disappears.

 

[Donald0039]

Good work
You can do a better job doing maintenance yourself!

And in many cases get the work done in a more timely manner. In my area of southern Delaware just finding a mechanic to work on an I/O is difficult.

With a newer engine a DIY person may need to splurge on a Diacom to read the codes and other diagnostic information.

 

[Lou C]

Yep at this point I'm basically independent of mechanics, outside of an internal drive problem, I have a spare drive I want to get rebuilt, so I can swap them if needed, I have a bunch of spare 4.3 Chevrolet parts, Rochester Quadrajet parts, a spare Prestolite points distributor and an OMC Cobra shop manual. I order parts I might need over the winter, the only thing I pay for is bottom paint on the boat.

 

[Lou C]

I experienced this with my 95 Four Winns 190 Horizon and Volvo 5.0 EFI at about 250 hours since new. With the outdrive trimmed up all the way, the exhaust bellows can be disconnected from the transom side to inspect inside the bottom end of the Y pipe. The flapper valves in my boat were rubber coated aluminum. One flapper came loose and partially blocked the exhaust in the transom area. This caused a significant power loss, and a loss of 12-15 mph top speed. We were able to fish a wire down through the y pipe and retrieve the flapper with the elbow and the bellows opened up. Some exhaust comes out under the transom shield around the transom anode at idle, but most of the exhaust goes through the prop hub at higher speeds. I also changed the anode and found a pin. The flapper installation includes the flapper, the pin, and the two rubber washers. A retrofit kit replaced the rubber washers with rubber flanged bushings.
The transom exhaust port is not as deep in the water as the prop hub, so less resistance for exhaust at idle. Hopefully, the hose between the exhaust elbow and the Y pipe can be positioned to cover the flapper pin holes or slots. You might also use tape and or silicone sealant on the holes according to the Service Bulletin. I experienced this also, but I was able to reposition the hose to stop the leak. Google "Volvo Penta flapper valve service bulletin" to find the Service Bulletin. Hope this helps.

The part that still puzzles me is Volvo/OMC using plastic parts in the exhaust system. These plastic parts and the rubber hoses are subjected to the water/exhaust, but generally are not compromised in normal use. Yet, if a plastic flapper comes loose and goes down to the bottom of the Y pipe further away from the combustion heat, many have said that the flapper melts and disappears.

They use rubber coated flappers because if they were all metal they would constantly tap tap tap and drive you nuts because it sounds like a bad lifter or engine knock. Mercrusiers are the same rubber coated flappers, metal inside.

the problem I have with Volvo is this:
if I recall correctly, they didn't require that you measure the static water line of the boat (the height of the exhaust elbow over the water level in the exhaust Y pipe) before telling you, just toss the flappers. Well, if your static water line is too low (less than 13" let's say) and you slow down fast guess what can happen? Your engine takes a gulp of water and if it doesn't stall instantly it will hydrolock and bend a connecting rod. Now it's new engine time.
For the record I have had the same Cobra/Volvo style flappers on my boat, 20 years worth of salt water boating, some in very rough conditions in and around Long Island Sound and NEVER had a hydrolock problem, and my static water line is just at 13". One time I had to change them due to an overheat. Not really a big deal, you do what you gotta do. A hydrolock & bent con rod, is a big deal. Volvo SHOULD HAVE SAID, YOU MUST MEASURE THE STATIC WATER LINE AND IF TOO LOW INSTALL HIGHER EXHAUST ELBOWS.
So basically I'm disagreeing with the experts at V/P. Remove em if you want but make sure to measure your static water line.

 

[4now04]

In '96 and '97 when I had my flapper valve issue, Volvo had a drill fixture ($100) to drill new larger holes, and a repair kit that included 4 new flanged rubber bushings that were to be glued in place with 3M 1300 or equivalent adhesive, and new pins and flappers. I received and installed the parts, but the following winter my dealer called asking if I was going to pick up the drill fixture. I declined. because the job was done and I didn't need it. The rubber flanged bushings prevented contact between the pins and the Y pipe. The instructions for the drill fixture said to rotate the fixture to drill new holes. The hose connecting the elbow to the Y pipe should seal any holes, or some tape could also help.