Dry Joint Manifolds and Risers

aero3113

My 330 has dry joint manifolds and risers, my 242 had wet joint. I’m curious if dry joint have a longer life span than wet joint or the same?

aero3113

I’ve read that with wet joint, you want to replace them before the water passages corrode and can potentially let water into the cylinders. With dry joint, you can wait until you see a slight rise in temperature because there is a highly unlikely chance water can get into the cylinders.

YYZRC

Are your risers/manifolds original?  How about your transom assemblies?  I'm fairly certain mine are original.

From what I can tell, my boat spent its entire life in the Mamaroneck area.  I have the Seacore parts so I'm hoping the transoms are ok.  I'm debating having the marina pull one of the risers to inspect.

aero3113

No, port manifolds and risers were replaced 8/29/14 (towards end of season) starboard were replaced 2018. My starboard transom assembly has a newer style decal than the port side, not sure if that means one was replaced or not. I don’t have any records on them.

YYZRC

My transom assemblies have what seems like 1/4" of anti fouling paint on them.  The original manuals came with the boat and I have the serial numbers of the original transom assemblies so I will compare next time I'm at the boat.  Not sure how to tell if/when the risers were replaced other than to say that they are OEM Merc parts and I suspect the PO would have gone with aftermarket if they were replaced.  10 years in salt water seems like a long lifespan, though.

aero3113

@Alswagg , do you have any input on when dry joint manifolds and risers should be replaced? I’m in salt water and my port side is going on 6 years. No overheating at all and I was able to keep my hand on the risers with the engine at temp. Do they have a longer life span then wet joint since they’re a totally different design?

aero3113

Port side was replaced towards the end of the 2014 season.

rasbury

I may be way off, but, if you have closed cooling then your manifolds would last as long as the block? When I had my motor out I replace my risers but as the manifolds never see water I saw no need to do anything with them. I suppose if you had an overheat and they warped and leaked you would but would suspect if that was going on you have more than manifolds for problems...and I did get aftermarket.

aero3113

@rasbury, do you have dry joint?

rasbury

Yes

aero3113

How long were your risers on for? How did they look when you replaced them?

rasbury

The boat is an 05 and I don't believe they ever had been replaced until last year...

aero3113

How did they look since they were on so long? 

J3ff

wondering the same about what needs to be replaced on a closed cooling system

rasbury

The risers looked ok except where the rubber boot attached. That was crumbling. There was no visible corrosion on the outside and nothing leaked. I just assumed they had never been done. There are 6" spacers also and I just cleaned those up, they looked fine and kept going. I did get aftermarket risors from a recommend from another site and we're half the cost of the Merc and exact match. Best China can make. The Merc ones probably made in the same plant so I did not feel to bad about it. 

aero3113

That's good to know. I would think the only reason it was bad near the boot is because the water can sit in-between the boot and riser.

rasbury

I was really thing I would have to replace it all- I think I did all of it for less than 500 bucks...

PickleRick

Are you guys full system closed loop cooled or half?

On a half system only the engine is closed loop, the manifolds/risers see raw water.

rasbury

My manifolds do not see water. 

aero3113

@rasbury , I could be wrong but doesn’t the seawater have to go through the manifolds to get to the risers?

aero3113

I see now, no raw water in the manifolds.

PickleRick

With those being dry manifolds and closed loop cooled they would last 10...20 years...maybe longer.  The risers in salt water should maintain the standard 3 to 5 years. 

Point being, your manifolds should never see salt so id imagine they would last the life expectancy of the motor.

rasbury

Yep.. I did  not really know it, but closed cooling was a must on my purchase and now I know why...

PickleRick

If i ever repower a closed loop system would be a must.  Closed loop systems are rare on boats in my area. 

YYZRC

@Aero, are you replacing your power steering ("transmission" in the diagram above) cooler?  I might do mine, I think it's under $200...

aero3113

@YYZRC , do you mean power steering fluid cooler? I was thinking about it, easy preventative maintenance.

aero3113

It’s strange they call it a “transmission cooler“ in that diagram.

PickleRick

If it's like the alpha one its easy to get to if you can stand on your head, i have no idea why they would call it a transmission cooler other than i run atf in mine.

rasbury

I replaced my power steering cooler when I had my motor out. Where the temp sensor threads in had broken off and the PO had glued it back on! I would say unless you see a problem, not much there to wear out or a reason to replace as a maintenance item near as I can tell..whole thing is very soft brass and easy to damage.

aero3113

@rasbury , you don’t think the brass can break down internally and could cause a power steering fluid leak you won’t see? The leak would just get pushed out the exhaust.

YYZRC

aero3113 said:

@rasbury , you don’t think the brass can break down internally and could cause a power steering fluid leak you won’t see? The leak would just get pushed out the exhaust.

Aero, are you able to find the part #?  I'm coming up with 863841T but that doesn't seem right based on the description ("Tube Water Brass").