Can Someone Explain This Please?

[Old Vet]

I found this statement in another thread.

"When was the last time the exhaust was serviced, as in manifolds and riser inspected and gaskets changed? this is the biggest killer of marine engines and is often neglected"

Why is this? Can someone explain/clarify the second line please? What kind of "servicing" is required?

 

[Summer Fun II]

For saltwater boats they are checking to see how bad they are corroded on the inside.
A few motors get ruined from rusted & leaking manifolds.

Thats what I was told to check if I ever bought a saltwater boat.

 

[390x]

Manifold/riser joints corrode over time which allows water into the exhaust that can/will then be ingested back into the engine.

 

[Old Vet]

So what's the "servicing" routine? Removal of the manifolds and visual inspection?

Are the "flappers" the main concern?

 

[390x]

Pretty much, disassemble, inspect, new gaskets, re-assemble.

 

[88dancer300]

Yes remove and replace riser gaskets, look for any signs of water intrusion in to the cylinders, check spark plugs for signs of rust. As a salt water boater, with raw water cooling on previous boats, I check and replace every two years even if I dont see signs of leakage. Many times they will leak on the inside, and you will never know untill you bend a push rod or blow a head gasket, or there is water in the oil.

 

[floriduramax1]

I hope I'm not derailing the thread, but are there advantages to the "dry joint" system over the traditional systems as far as longevity in salt water?

 

[88dancer300]

Dont understand what you mean by dry joint? Please explain. Thanx.

 

[floriduramax1]

Dont understand what you mean by dry joint? Please explain. Thanx.

I'm not 100% sure, but dry joint manifolds is what I have. I haven't really taken the time to read about them yet but I did buy 2 full sets of manifolds risers and everything that is required to change them. It looks like the water flows outside through separate passages as opposed to side by side with the exhaust in the risers/spacers.

 

[88dancer300]

:huh:HMM...New to me, got any pictures?

 

[Summer Fun II]

Read this. :smt001. http://www.ebasicpower.com/faq/dryjointexhaust.htm

 

[88dancer300]

Wow, I like that exhaust ! The water jacket size is much bigger and should allow scaling to pass right through, unlike the standard exhaust that is prone to clogging. That's going solve a lot of problems. Big $ I bet.

 

[Ididntdoit]

I just completed helping a buddy do the job on a 2003 280 DA 4.3 (dry joint) took us 8 hours for all 4 - parts (manifolds, risers, 4 inch spacers and gaskets) were $3500 - there is no aftermarket source for dry joint - I can tell you after 7 seasons (5mos yr in new england waters) on a raw water cooled boat they did not look that bad at all - of course I could not see inside the water jackets of the manifold that well - I can tell you the "holes" the water passes through from the manifold to the riser were not corroded at all and the "snout" of the elbow, while surface rusted, was not corroded either. I'm told the service life of any manifold is not linear and that is once they start going they can go quickly. Based on what I saw the dry joint system eliminates one of the worst culprates for manifold failure (the windows around the exhaust outlet) and if I had a boat built prior to 2001 I would without question spend the extra bucks upgrading to dry joint on my next manifold change - this is one thing merc got right!

 

[88dancer300]

Wow, thats $7000.00 for twins!

 

[Summer Fun II]

Boats that are 2004 or Newer its a lot cheaper. :smt089. http://bpi.ebasicpower.com/mm5/merc...rchterms3=1&srch_srchterms4=1&srch_malterms=1

 

[tdschafer]

My buddy just had these priced out for his 2003 280 DA. The total for both engines was $3000-3500. My mechanic buddy explained that dry joint is more expensive because they are still under patent from mercruiser and there is no after market availability to provide downward cost pressure.

I agree that the design on these seems MUCH better than the old style which begs to ask the question: What took so long? :huh:

 

[Ididntdoit]

My buddy just had these priced out for his 2003 280 DA. The total for both engines was $3000-3500. My mechanic buddy explained that dry joint is more expensive because they are still under patent from mercruiser and there is no after market availability to provide downward cost pressure.

I agree that the design on these seems MUCH better than the old style which begs to ask the question: What took so long? :huh:

Yes correct - my buddies boat is twin 4.3 - the time and amount was for both engines - as for what took so long - ?????????

 

[Jdr01930]

Yes remove and replace riser gaskets, look for any signs of water intrusion in to the cylinders, check spark plugs for signs of rust.

How much is this inspection likely to cost? (assuming you don't actually end up needing to replace risers etc)

 

[fwebster]

Takes an experienced mechanic about an hour, if the risers have been broken apart previously for inspection, and if correct gaskets are there.

 

[Jdr01930]

Thanks Frank - I was hoping it didn't require a total engine tear down (inboard/outboard noob here!).
Incidentally this thread inspired my to finally post my questions about how this stuff relates to the new catalyzed "ECT" engines. Been meaning to bring it up for months.