LIFTER VS MANIFOLD/EXHAUST LEAK

Discussion in 'General Maintenance/Repair Questions' started by LunaSea290, Jun 27, 2022.

  1. LunaSea290

    LunaSea290 New Member

    28
    Jun 13, 2019
    290 Amberjack 2006
    350 Horizons, V-Drives
    Good day all. A problem has come up with one of my engines and I'm in the process of figuring out what's wrong and some input from everyone would be greatly appreciated. I have a 2006 Sea Ray Amberjack with 350 MPI Horizon motors, V drives (serial# range OW39000). There are approximately 525 hours on the engines. This is going not my 4th season with the boat. When I got it I was told that the risers and manifolds were done and it was evident that at least the risers were done (bolts turned and exposed unpainted surfaces). My fault for not obtaining written proof. With that said, I've developed at ticking sound on the port motor. The ticking remains constant with the rise and fall of RPM's. This was first noticed when using the boat this past weekend. Ran the boat at 3500 rpm's for about 30 mins. Temps were at 163 each engine. Did my first drift and when I restarted the motors I noticed the ticking. Continue fishing and then made the run back in. About the same amount of time returning to the slip. When backing in I noticed the ticking had quieted. Let the motor set for a while 10 mins or so and restarted. The ticking came back. The other thing I noticed was if I give the motor some throttle and drop it down to idle, the ticking will fade and then resume once at idle. I used a stethoscope and check the valve covers, heads, flywheel housing, pulleys, pumps etc. I never picked up on a "internal" click or tick. The sound seems external. There is rusts scale on the manifolds by cylinders 7 and 8. there is some rust on the underside of the others.
    I've given as much information regarding the issue. Before I'm committed on a diagnosis I would like to hear what anyones thoughts are. Might be something I'm missing. Thanking you in advance.
     
  2. scoflaw

    scoflaw Well-Known Member

    Aug 10, 2011
    cape cod mass, cape coral fl
    1999 Powerquest legend 260 sx 502 mag
    2005 Baja 242 islander 496
    502 mpi Bravo 1
    496 mag B1
    could be a blown exhaust gasket, you'll see carbon tracking with a light under the manifold
     
  3. doozie

    doozie Active Member

    509
    Dec 6, 2007
    MIDDLE RIVE MD.
    46 sundancer 2001
    3126B 450hp Cats
    Could be a spark plug wire, old, cracked, arcing to ground
     
  4. LunaSea290

    LunaSea290 New Member

    28
    Jun 13, 2019
    290 Amberjack 2006
    350 Horizons, V-Drives
    Thanks for the reply. Ya, leaning in that direction. It's a bit cluttered (hoses, plug wires) and I've been trying to see as much as I can. Still looking.
     
  5. LunaSea290

    LunaSea290 New Member

    28
    Jun 13, 2019
    290 Amberjack 2006
    350 Horizons, V-Drives
    Thanks for the reply. Wouldn't an arcing plug wire(s) cause the motor to run rough? The motor seems to be running smooth, no hesitation. I do have a spare set and will be replacing them anyway. Have to see how that works out.
     
  6. techmitch

    techmitch Well-Known Member PLATINUM Sponsor

    May 1, 2008
    Chesapeake Bay, Middle River/Frog Mortar Creek MD.
    1999 270 DA
    Twin 4.3s W/Alpa I Gen II's
    You can use your mechanics stethoscope without the sensor wand, i.e. just the hose (with an extension hose and a coat hanger lightly twisted around the end for positioning. This method works great for finding small exhaust leaks as the extension with the coat hanger really lets you put it where you want it.

    I hope you find an exhaust leak but the highlighted part sounds like an oil pressure issue to me.
     
  7. LunaSea290

    LunaSea290 New Member

    28
    Jun 13, 2019
    290 Amberjack 2006
    350 Horizons, V-Drives
    Thanks for the reply. Great tip with the wire hanger. I'll give it a try. Nothings off the table. From what I saw with my oil pressure gauges everything is in normal range. I'm gonna triple check that today.
     

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