Y pipe replacement

[JoeRJGR]

All,

1984 Mercrusier 260 5.7 Liter: Was taking on water a couple weeks ago along with a gurgling sound. . Pulled the boat, pulled off the elbows and ran water through both sides of the Y pipe with a hose....saw the water coming in from very bottom of the transom. Have to assume it is the Y pipe....FYI, the flappers were fine...

Someone close by has some used Mercruiser parts for sale: They have a Y pipe from a 1990 5 liter. I assume this will fit? Should I also pick up a transom shield if cheap enough? I'd like to have everything I would potentially need (within reason) before I pull the motor. I know there is a gasket for the Y pipe...anyone know the correct name so I can order it?

Thanks for your help.....any other tips would be welcome.

Thanks

 

[alldodge]

The Y pipe fastens directly to the transom assembly. The inner plate is not connected. Unable to say if your transom assembly also has a problem, but in all cases I've seen it has only been the Y pipe

 

[tank1949]

You will need motor and transom seral numbers to be precise. There are some very knowledgable people supporting this forum but they most likely will need numbers. Some of the really old MC y-pipes have different bolt patterns than later ones. If salt water boat and that old, expect a lot more to replace and possibly a transom rebuild. Sorry, but boats are a pain in the butt. If fresh water boat, the aluminum doesn't "cancer" as much, if at all, and you may be able to get by with only replacing rubber o ring looking Y-Pipe seal. Be sure to order the "formed" o-ring seal and not just a round one. The round ones are impossible to keep inside grove while you retorque Y-Pipe bolts (they were for me). Don't lose bolts because they are priperiatry. Obviously, you will have to pull motor, have a stand and place to keep motor, while you work in your bilge area. If you can access area, you might want to plug exhaust port on the outside part of gimbal housing (with motor out) and use garden hose to fill Y-Pipe. If water only comes out of area where Y-Pipe is connected to gimbal housing, you may have dodged the transom rot bullet. However, that old of boat, I suspect rot too. I have been working on a 1986 rebuild for over 3 years. I feel your pain! Good luck.

 

[JoeRJGR]

I was under the impression that the Y pipes were fairly universal...no?

 

[achris]

You will need motor and transom seral numbers to be precise. There are some very knowledgable people supporting this forum but they most likely will need numbers. Some of the really old MC y-pipes have different bolt patterns than later ones. If salt water boat and that old, expect a lot more to replace and possibly a transom rebuild. Sorry, but boats are a pain in the butt. If fresh water boat, the aluminum doesn't "cancer" as much, if at all, and you may be able to get by with only replacing rubber o ring looking Y-Pipe seal. Be sure to order the "formed" o-ring seal and not just a round one. The round ones are impossible to keep inside grove while you retorque Y-Pipe bolts (they were for me). Don't lose bolts because they are priperiatry. Obviously, you will have to pull motor, have a stand and place to keep motor, while you work in your bilge area. If you can access area, you might want to plug exhaust port on the outside part of gimbal housing (with motor out) and use garden hose to fill Y-Pipe. If water only comes out of area where Y-Pipe is connected to gimbal housing, you may have dodged the transom rot bullet. However, that old of boat, I suspect rot too. I have been working on a 1986 rebuild for over 3 years. I feel your pain! Good luck.

What is it with you and salt water boats? My 1972 boat is in perfect condition, no rot in the transom or anywhere else. And the only fresh water that boat has ever seen is when it rains.
As for engines, the original came out after 22 years and was, for its age, in reasonable condition. The 4.3LX was 12 years old when I pulled it out, and all the screws came out like they'd been put in the week before. The current 4.3MPI is 14 years old and there's no signs of any problems. And as a diver the bilge see plenty of seawater. It does get drained after each trip, but that's all. Salt water isn't the big bad Boogie man you seem to portray it as....

Chris....

 

[alldodge]

I was under the impression that the Y pipes were fairly universal...no?

Not for your year. The transom assembly has been changed and starting in 1989.

You can have a one piece or 3 piece exhaust Y pipe. The 3 piece has other sealing surfaces which come into play. The bolt patten of yours is different then the more modern one

Note the bolt patten is also different then the newer design

 

[Lou C]

Salt water use is not the kiss of death some think it is. My boat is 32 years old, the transom assembly, drive and Y pipe are original, it has been used in salt water close to 20 years (was originally a freshwater boat from the Midwest). I've had it moored in salt water at least 15 years for 6 months of the year. I have not had unusual problems due to salt use, I have replaced the exhaust system every 5-7 years. 3 sets of OMC batwings including the ones it came with and now on the 4th set I converted to the late OMC/Volvo 2 piece system. The boat has never been flushed till the end of the season because it sits on the mooring. The one thing I've always done is to fill the engine and manifolds with either -100 marine AF or Sierra no tox AF when winterizing. Not sure if this helped but I think it has. When I did a top end overhaul 3 years ago the cooling passages in the head were getting eroded from salt water use and at the machine shop's recommendation I replaced them with a nice reman set of pre-vortec heads. The 4.3 short block is still 100% original as it left GM in Tonawanda, NY. Compared to outboards this is not unreasonable, they have the same problems sometimes worse. If I do re-power this boat with a reman or new engine for sure I will add a half closed cooling system, and a remote oil filter mount.
The main problem I have had is marine growth on the drive and keeping anti fouling paint on it.
I have read and heard that it is rain water that causes most of the rot in boat wood structural members, I'm not sure if this is true but has been repeated many times. Salt preserves wood rain water rots it. In that regard, much of your outcomes are a result of how the boat is stored. If it is kept out of the weather not in a constantly damp environment you will have much less trouble with rot. Here the climate is hot and damp in the summer, and cool/cold and damp in the winter, so wood cored boats are challenging to make last, I replaced much of the deck on my boat and repaired rot in a few other areas as well. Its always been covered in storage but the moisture you cannot do much about.

back to the question, you have to use serial numbers to be sure of getting the right part, there were several variations...

PS Chris, when I did the top end overhaul I did not break one bolt, I used my De Walt 1/2" drive electric impact gun to remove the cyl head bolts, and intake bolts. All the accessory and exhaust fasteners came right off. Oil pan (sprayed every other year with corrosion X) is original too. However, I did replace all the head bolts with ARP head bolts (corrosion)….

 

[tank1949]

What is it with you and salt water boats? My 1972 boat is in perfect condition, no rot in the transom or anywhere else. And the only fresh water that boat has ever seen is when it rains.
As for engines, the original came out after 22 years and was, for its age, in reasonable condition. The 4.3LX was 12 years old when I pulled it out, and all the screws came out like they'd been put in the week before. The current 4.3MPI is 14 years old and there's no signs of any problems. And as a diver the bilge see plenty of seawater. It does get drained after each trip, but that's all. Salt water isn't the big bad Boogie man you seem to portray it as....

Chris....

Chris, I am 71 years old and I have owned at least 7 salt water usage boats and all suffered with rust and corrosion, and I had to constantly monitor or maintain them. 5 were Chevy V8s. OMCs were the worst. All I/O owners learned years ago in this area, and I have known several, to never store their boats wet in salt water. Flushing with fresh water increases longevity, but cast iron risers are the first to clog and rust/rot out internally, followed by cast iron manifolds experiencing the same problems. Sea water cooled motors last about 8 years hear with heads "cancering" first. I replaced 2 Chevy motors. One's head rusted through and motor hydro-locked. So, I replaced the pair at one time. Owners here can wash down iron motors after they cool off and get reduction of some external rust, but they also have to coat with a rust inhibitor. I have had to replace several MC trim solenoids due to SW dripping onto them and causing issues. The Sea Ray MCs that I have owned were wet deck boats and salt spray constantly leaked into the engine compartments and on engines until I figured out how to redirect the water. I have replaced ( I believe 4) Y-Pipes and all due to saltwater corrosion or cancer. A couple more just became dislodged from activities. Perhaps the Gulf of Mexico where I boat has more salinity than where you boat? However, people who can afford it, have been going to 4 stroke OBs for reasons: safety and longevity. I am not going to waste 60 grand on two 300 HP Yamaha OBs to push my boat the way I want it. I am too old to learn new technology and I like to have money in my bank account. Besides, working on my rebuild, provides me a legitimate excuse not to have to listen to my wife complain about politicians. LOL

 

[JoeRJGR]

Guys,

Engine engine serial number is 6744513, transom assembly serial number is 6747316, stern drive unit serial number is 6726813.

The part number I got from the MerCrusier part catalog is 807130A4. I have someone near my home selling a used Y pipe from a 1990 5 liter for $100. On a previous post, I received comments that the Y pipes were all the same...

I really want to have the correct part in hand when I pull the motor.

Thanks again for all your help.

 

[tank1949]

Guys,

Engine engine serial number is 6744513, transom assembly serial number is 6747316, stern drive unit serial number is 6726813.

The part number I got from the MerCrusier part catalog is 807130A4. I have someone near my home selling a used Y pipe from a 1990 5 liter for $100. On a previous post, I received comments that the Y pipes were all the same...

I really want to have the correct part in hand when I pull the motor.

Thanks again for all your help.

They are not the same! I believe that in the late 80s, MC changed the design for Chevy V8s. Look at bolt pattern and compare them would help.

 

[JoeRJGR]

cant tell what the bolt pattern is till I pull the motor!

 

[alldodge]

Take your phone and place on vid with flash lite ON, then start going all over back in close. Then replay and see if there are 2 bolts on top next to each other or just one with another still on top but lower to the left. Like pic showing bolt pattern in post 6

 

[jdklein001]

One piece of advice I got here about y pipes was to buy new. I was considering buying used from ebay (couldn’t see it first) and the logic I received was in the form of a question asking if pulling the engine again was worth the 200.00 in savings I was looking at if the replacement pipe went bad quick

 

[JoeRJGR]

Yea, I hear that about the pipe....JD...

All Dodge, Thanks for the pics and advice, I'm having a hard time visualizing from those pics. I remember seeing the two top bolts next two each other. They are not offset. They are only bolts I can see, and they are silver in color.

Thanks for the help...

 

[JoeRJGR]

All Dodge, as mentioned above, I see the two bolts on the top..does that make it the newer or older product?

Want to order this part and get it done.

Thanks

 

[alldodge]

Sorry went out of town

The new style uses the 2 holes close together on top. So if yours shows them as in the pic you should be good

 

[JoeRJGR]

Yep they are the only two I can see....have any new on nice pipe....thanks for your help!