[Question] first jet boat need some help
+ Reply to Thread
Results 1 to 11 of 11

Thread:
first jet boat need some help

  1. #1
    Junior Member
    Join Date
    May 2018
    Posts
    4

    Default first jet boat need some help

    so I had it out once now have water in the oil putting in another motor next week but my question is could this have been my fault ? a friend told me the valve for the water inlet cant be all the way open [that's how I had it] so is that true or ? the rubber flaps are also not there I noticed after could that let the water into the exhaust I have an older style with the snail looking mufflers ? thanks
    Last edited by 8844e4e6; 05-09-2018 at 08:32 PM.

  2. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  3. #2
    Senior Member
    Join Date
    Dec 2007
    Location
    New Jersey
    Posts
    307

    Default

    It would be easier to offer suggestions and opinions if you gave some details on the engine, drive and boat. Pictures are also very welcome.

    Water in the oil can happen any number of ways. Could be blown head gasket, blown intake manifold gasket, cracked block, too much water pressure from the pump etc. Some people run a pressure relief or pressure regulator between the pump and the engine so they don't over pressurize the water passage, some times people just partially close the valve from the pump.

  4. #3
    Junior Member
    Join Date
    May 2018
    Posts
    4

    Default first jet boat need help

    sorry about that its a 78 Tahiti with a 460 has the hardin marine exhaust water log style with the snail looking mufflers [will add pics] and a Berkley jet no place diverter or anything tried to upload pics but too large will do so later today
    Attached Images Attached Images          
    Last edited by 8844e4e6; 05-10-2018 at 03:36 PM.

  5. Remove Advertisements
    PerformanceBoats.com
    Advertisements
     

  6. #4
    kenny nunez
    Join Date
    Oct 2014
    Location
    Kenner, La.
    Posts
    72

    Default Water in the oil

    Also take a close look at the timing cover, there are some areas that are thin and may be eroded.

  7. #5
    Junior Member
    Join Date
    May 2018
    Posts
    4

    Default

    will do pretty sure I'm good there but ill look anyway going to prep and paint new motor this weekend then run a compression check on the old one see what it looks like while everything is still hooked up then install the new one next weekend just don't want to make the same mistake twice especially one so expensive thanks

  8. #6
    Senior Member usual suspect's Avatar
    Join Date
    Apr 2009
    Location
    So. Cal
    Posts
    1,037

    Default

    You need to run a valve to lower the water pressure from the pump or it will milkshake the oil, and if you are running thru transom exhaust the flaps are also necessary. You want to try to get the engine temp to run about 130- 170 so keep the water pressure lower to get the engine temp up.
    It might take a few adjustments between running it to get it right.

  9. #7
    Senior Member Mouzer's Avatar
    Join Date
    Mar 2008
    Location
    corona ca
    Posts
    19,597

    Default

    i bought a jet boat from bob at elim.....he called me had a smokin deal....18ft jet built 427 but had water in the oil...so i grabbed it cheap noticed the valve on the pump was wide open.......i changed the oil twice and turned the valve down and shut water off to headers and used it all summer with no water in oil....


    ''''''OWNER OF THE BIG WHITE WOLF....,,,
    ,,,

  10. #8
    kenny nunez
    Join Date
    Oct 2014
    Location
    Kenner, La.
    Posts
    72

    Default Water in the oil

    Because the water is going through the engine so fast it is condensing the water. Other than using the valve the best thing is a thermostat kit from one of the suppliers on this site.

  11. #9
    Junior Member
    Join Date
    May 2018
    Posts
    4

    Default

    Thanks everyone I appreciate the help did a compression test was 120 more or less across the board already grabbed another long block so going to install this weekend once I have it out I'll break down the old one and inspect further never hurts to have a spare think it probably was the water pressure but I didn't put it together so I'd rather have the piece of mind that it's put together right anyway I'll post again when I know for sure

  12. #10
    Re-member
    Join Date
    Feb 2009
    Location
    bay area ca.
    Posts
    146

    Default

    my guess is the boat looks like its complete and has been running for quite a while. its not like you changed anything other than opening the valve all the way. its possible that could be the problem but I doubt it. as long as your water outlet isn't restricted you wont build or shouldn't build too much pressure. if you just bought the boat I would say it has a cracked block. what part of the usa did it come from ?

  13. #11
    Junior Member CatDrag's Avatar
    Join Date
    Jun 2018
    Posts
    18

    Default

    I know (the hard way) that hooking up a garden hose to provide cooling water to the engine is a risky endeavor. If the water flows and the engine is at rest (off), the water can find its way into the open exhaust valves, hydrolocking the engine and maybe finding its way into the oil. Tough lesson for me to learn. lol. All is good now on my girl "RONI", a 20' 1986 Bahner open bow.

+ Reply to Thread

Quick Reply Quick Reply

Register Now

Please enter the name by which you would like to log-in and be known on this site.

Please enter a password for your user account. Note that passwords are case-sensitive.

Please enter a valid email address for yourself.

Please select your insurance company (Optional)

Log-in


Tags for this Thread

Digg This Thread

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •  
 

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95