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Manifolds and Risers


How often, or will you change your manifolds and risers ?  

69 members have voted

  1. 1. I run in brackish and or salt water mostly:

    • 1 year ~ 100 hrs.
      0
    • 2 years ~ 200 hrs.
      0
    • 3 years ~3 00 hrs.
      1
    • 4 years ~ 400 hrs.
      0
    • 5 years ~ 500 hrs.
      1
    • 6+ years ~ 600+ hrs.
      2
    • I'll sell my boat before it needs them.
      1
    • I'll keep running until I let the smoke out of the engine, then, I'll get a new boat.
      0
    • I only run in FRESH water
      53
  2. 2. I run in fresh water ONLY:

    • 1 year ~ 100 hrs.
      2
    • 2 years ~ 200 hrs.
      1
    • 3 years ~3 00 hrs.
      0
    • 4 years ~ 400 hrs.
      1
    • 5 years ~ 500 hrs.
      3
    • 6+ years ~ 600+ hrs.
      33
    • What are manifolds and risers?
      13
    • Can't I just pay someone to do it?
      4
    • I only run in BRACKISH or SALT water
      2


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I'm not embarrassed to say that :)

Maybe the problem is the poll. It forces you to vote for a question on the top AND the bottom. You need to give an offering for the top Q that says something like 'I only ride in fresh water'. And on the bottom something like 'I only ride in brackish water'. That way we can see the true results.

I only tried to vote for the bottom question, and it wouldn't let me.

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Voted 500 hours, but that may be wishful thinking. When I changed the thermostat this winter, I was surprised at how much rust I found in the housing. Never run in salt water so I assume this is normal, and due to the lack of anti-freeze and its anti-corrosive ingredients compared to an automobile engine. Dontknow.gif

Correction: I tried to vote. Andy is correct, it won't let me vote just for the bottom (fresh H2O) portion.

Edited by John I.
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Sorry guys,

I don't know what I did wrong when I set up the poll.

I asked Andy if he can fix it. You know him, Captain pollster.

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I wonder what the life span is on the Indmar aluminum headers on the 04 and up Monsoon and Hammerhead engines. Those won't be cheap to replace.

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Because they have water in them, they do rust out. And if you don't catch it in time, they can dump water into the engine through the heads and do serious damage.

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How do you know when you need to replace them. Mine have a little rust visible at the gasket between the manifold and riser, but it doesn't seem to be getting any worse. But I certainly do not want to wait until they are bad enough to cause damage to my heads.

Are they pretty easy ot take off and look into, with maybe just buying some new gaskets, or is it more involved than that?

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The couple that I have seen that needed to be replaced were leaking down the side of the engine. I do as much mantenance that I can but, I would have a real mechanic replace them as the bolts can break off and they need to be torqued down.

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In fresh water, you forgot the button for "never".

That would be when I'd change them, short of a leak. Good chance the boat, motor, manifolds and risers will all live longer than I'd ever own the boat. Some 20 year old boats have come through here with original equipment still on them, and still working.

Peter.

...but speaking of polls, what is "salt water" ? ;)

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The external walls of the manifold are thinner than the internal walls so in-theory if your manifolds started to rust all the way through you would develop a leak to the engine compartment before you would develop a leak into the heads. At least that is the theory.

Check out Pete using scare tactics to drum up some business. :lol:

j/k Pete ;)

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In fresh water, you forgot the button for "never".

That would be when I'd change them, short of a leak. Good chance the boat, motor, manifolds and risers will all live longer than I'd ever own the boat. Some 20 year old boats have come through here with original equipment still on them, and still working.

Peter.

...but speaking of polls, what is "salt water" ? ;)

Will the EXTs last as long?

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  • 2 weeks later...

This is an interesting question. I've been doing some reading on BoatUS forums, where people run all types of boats in all types of conditions and lots of people talk about replacing exhaust manifolds. One recent comment was that 9 years was a "REAL" long time for manifolds to last on a FRESH water boat. I was extremely shocked by this statement. But a lot of people agreed. I've never seen a fresh water boat need them, but maybe my scope isin't very wide.

Boat US Thread - A few guys talking about this exact issue

A quote from the above thread...

It is entirely common in the Great Lakes to get 20 plus years from exhaust manifolds. There is a 69 Cris-Craft near me in my marina, original manifolds, still going strong.

So it looks like their are a lot of opinions on this topic!

Edited by aneal000
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