Manifold/ Riser Question 8.1 Horizons

Discussion in 'General Maintenance/Repair Questions' started by Misterhelms, Jul 11, 2020.

  1. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Currently on a sea trial on a 2007 340 and 3 of the 4 risers are running hot around 195 degrees at cruising speed. The 4th riser on the far port side is showing 120 degrees. Any idea why 3 of the 4 risers would be running hot?
     
  2. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise
    Blockage?

    Type cooling? Age of manifold and risers?
     
  3. M Prod

    M Prod Well-Known Member

    Oct 6, 2017
    North Vancouver, BC
    2005 Sundancer 340
    Zodiac Cadet w/FCT console Yamaha F20
    Kohler 5KW Genny
    8.1 Horizons /V Drives
    This is a can of worms. Could be so many things. Insufficient water flow caused by ..laundry list of things. My guess is there may be clogs limiting water likely caused by excessive rust inside the manifolds. Either way it’s a problem. Is the boat in salt? Manifolds need to be changed every 5 years. Find out when they last did them.
     
    CaptRonn likes this.
  4. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Asking the owner now - probably better to be safe rather than sorry and replace them.
     
  5. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Guy has had the boat since 2007 and has not replaced the manifolds since he has owned the boat.
     
  6. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise
    Fresh or salt water?
     
  7. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Brackish - Chesapeake Bay
     
  8. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise
    The manifolds and risers are probably over due for replacement.

    Is it fresh water cooled or closed cooling?
     
  9. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Closed on the block - raw water on the exhaust
     
  10. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise
    Better factor in replacing risers and manifolds, plus labor.
     
    M Prod and Misterhelms like this.
  11. M Prod

    M Prod Well-Known Member

    Oct 6, 2017
    North Vancouver, BC
    2005 Sundancer 340
    Zodiac Cadet w/FCT console Yamaha F20
    Kohler 5KW Genny
    8.1 Horizons /V Drives
    Yup those are way way overdue. It’s going to be a $5k job minimum. Parts alone will be in the $3k range. Also make sure you check the oil assuming he’s hasn’t changed it recently. Check for water in oil etc. Its not typical for these dry joint manifolds to leak into the engines, but it will happen eventually. Then you’ve got a whole bunch more problems.
     
    Misterhelms likes this.
  12. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise

    For the OP, if you buy the boat and have this done post the pictures of the risers here.
     
  13. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Looks like the owner is going to get them replaced which is great. That was one of my main concerns about buying a boat. I took the below pictures today on the sea trial
     

    Attached Files:

  14. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Sorry - meant to say since 2017 not 2007.
     
  15. M Prod

    M Prod Well-Known Member

    Oct 6, 2017
    North Vancouver, BC
    2005 Sundancer 340
    Zodiac Cadet w/FCT console Yamaha F20
    Kohler 5KW Genny
    8.1 Horizons /V Drives
    Ah well then they shouldn’t be that bad. Might have something else clogging like failed impeller parts. Make sure that when they replace the manifolds, they do a good back flush through the system. I would ask them to go ahead and change the water pumps on each engine while they’re at it too.

    Good luck with it. Hope it works out. 340’s are great boats!
     
    CaptRonn likes this.
  16. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Thanks! We are excited. Good idea on the water pumps - what does that typically run?
     
    Last edited: Jul 11, 2020
  17. CaptRonn

    CaptRonn Well-Known Member

    973
    May 25, 2016
    on a large body of water
    1999 Sea Ray 400 Sedan Bridge
    Convert fuel into noise
    Water pumps. Each engine has a raw water pump with rubber impellers. The impellers should be changed annually. Now is the time to change them.
     
  18. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Sorry - meant the cost - to replace.
     
  19. M Prod

    M Prod Well-Known Member

    Oct 6, 2017
    North Vancouver, BC
    2005 Sundancer 340
    Zodiac Cadet w/FCT console Yamaha F20
    Kohler 5KW Genny
    8.1 Horizons /V Drives
    Each water pump for an 8.1 will run about $500 for the assembly plus labor. They’re a PITA to change. Not mechanically difficult, but logistically as each one is directly under the engine in that ridiculously tight bilge. I’d expect a mechanic to likely charge you $1500-$2000 to replace both, parts and labor.
     
  20. Misterhelms

    Misterhelms Member

    51
    Jul 5, 2020
    In Market
    Boatless
    Thanks!
     

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