350 Mag Ski Water Entering Rear Cylinders

Discussion in 'Gas Engines/Drives/Transmissions/Props' started by John Cooke, Nov 5, 2019.

  1. John Cooke

    John Cooke New Member

    6
    Nov 5, 2019
    Skiray Searay 190BR
    350 Mag Ski
    Discovered problem when motor hydrauliced and broke off starter motor bolts. Pulled plugs and found teaspoons of water coming out from rear 2 cylinders on both sides. Purged water and would run normally but on next start, same problem. I am getting very skilled at replacing broken starter motor bolts, but would prefer to fix problem. Any suggestions on where to start. I put a drain on water muffler just in case it was the source. No impact. This is an inboard for a 190 Skiray Searay. Any tips on resolving would be greatly appreciated. Thank you.

    P.S Anyone needing tips on extracting broken bolts without yanking motor can just ask. I have developed wonderful techniques now
     
  2. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    How old are the exhaust manifolds and risers?

    fresh or salt water boat?
    Closed cooling or raw water cooled?

    rotted exhaust, rotted cylinder heads, and rotted intake manifold are all things that come to mind.

    Could also possibly be a leaking intake manifold. What does the oil look like? Normal color or does it look like a milkshake?
     
  3. John Cooke

    John Cooke New Member

    6
    Nov 5, 2019
    Skiray Searay 190BR
    350 Mag Ski
    Hi Espos. Thanks for responding.


    Everything is original. Boat is 1996 Skiray so 23 years old, fresh water raw cooling, only about 500 hrs.

    Oil looks fine.

    The odd thing to me is that both sides of the engine have the identical problem and degree of water, meaning the failure happened at almost the same time/month.

    Do you recommend exhaust manifold inspection first and then move onto intake heads and then heads? Engine runs better than ever and has no external corrosion but our lake is quite acidic based on the rust on chains the holding my dock, so your suspicion on rott may be correct.
     
  4. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    I would start with inspecting the risers/manifolds. What you are seeing is a typical failure. Once the water jacket in the manifold or riser is compromised, water can leak back into the exhaust portion of the manifold after you shut the engine down - the water will go to the lowest point (rear cylinders) and through an open exhaust valve and into the cylinder. You broke the starter bolts because the engine was hydrolocked (water in the cylinder(s)) - water won't compress, so the engine would not turn over and broke the starter bolts - this could have just as easily broken something in the motor (connecting rod, wrist pin etc) and at that point you have a big problem. So don't do that again - you need to pull the plugs and spray some fogging oil into the cylinders to prevent any rust while you figure this thing out.

    If the manifolds are in fact the problem, there are a number of ways they can fail - corrosion from a salt water environment is the most common, but freezing and overheating can also cause them to fail. You don't say your location, but could this motor have freeze damage? I think it is unlikely they are rusted or corroded being a freshwater boat. It is also strange that both sides are doing this at the same time, but it could happen that way. In freshwater manifolds/risers generally last forever. I have never replaced a manifold in my freshwater engines.
     
  5. Espos4

    Espos4 Well-Known Member

    Jan 1, 2017
    Long Island NY
    2007 240 Sundeck
    350 MAG Bravo 3 W/DTS
    I’m not familiar with your inboard exhaust design. I/O’s have Rubber flaps that help prevent water from rushing back in if you come off plane too fast.

    Is there some similar flap(s) on your inboard setup that perform the same function?

    Maybe that failed and water could enter that way.
     
  6. BillK2632

    BillK2632 Well-Known Member GOLD Sponsor

    Jun 25, 2009
    Lake Norman, NC
    1999 185 Bowrider,
    Mercruiser 4.3, Alpha I
    That's a thought, those older inboard ski boats (like my old Correct Craft) only had a flapper on the outside at the very end of the exhaust pipe - outside of the boat.
     
  7. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    The Sea Ray archives lists the 190 Ski Ray as an outboard model only in 1996. However, there is a Sea Ray Spitfire SS listed and on the pictures, the graphics on the side of the boat say SKI RAY. This boat is a straight inboard. Is that yours?
    skiray.png

    If it is you need to remember that the motor in that boat does not sit level and any water getting in will sit at the lowest point which in your case the back of the motor. Also, if your 23 year old boat has the original manifolds on it there is a very good chance they are bad. Sounds like a good winter project to me.
    Shawn
     
  8. John Cooke

    John Cooke New Member

    6
    Nov 5, 2019
    Skiray Searay 190BR
    350 Mag Ski
    Thanks everyone. Freezing is very possible as the boat is in Canada, and I did have an overheat event after launching one time and the system did not prime. I hope it is just the riser/ manifold as I feel comfortable with that job. I will confirm when I get it torn apart. External flapper is all for this inboard and it looks to be in good condition. I was hoping someone would suggest replacing 350 with a 454 but I am not sure the extra weight will make the wake any smaller . Have a great Thanksgiving everyone!
     
  9. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    You rarely see a 454 in that size ski boat and I'm pretty sure it wouldn't fit under the engine cover. Besides....how fast do you want to ski?
    Shawn
     

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