User Tag List

Page 1 of 6 1 2 3 4 5 6 LastLast
Results 1 to 15 of 83
  1. #1
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    1985 Mercury 150 Black Max overheating

    I have a 1985 Mercury 150 Black Max that is overheating as soon as you put the power to it. It will idle at 145 degrees all day but as soon as you raise the RPM's it gets hot and the alarm goes off. It does not cool down after it gets hot. It has a brand new water pump, thermostats and poppet. The motor was just complete apart (except for splitting the block and pulling the crank). everything is clean and the water passages are clear. Could this be a malfunctioning poppet valve? Could the spring be too strong for the water pump to push it open? I am thinking that when under power the poppet is not opening and that the thermostats do not let enough water flow to cool the motor. Am I on the right track? What would happen if I ran no poppet and ran just a dump off the poppet? Would it build enough heat with a dump off the poppet and no poppet inside?

    Any opinions or help would be greatly appreciated.
    Jeff

  2. #2
    Join Date
    May 2012
    Location
    Savannah GA
    Posts
    387
    Thanks (Given)
    1
    Thanks (Received)
    7
    Likes (Given)
    1
    Likes (Received)
    2
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    sounds like you still have a clog. I doubt it is the poppet valve. but you could try running it without it. is one head getting hotter than the other? did you run the new water pump impeller dry even for a few seconds? did the you flush the tube going up to the head good? is the tube fitting into the water pump snugly? seems like there is a rubber piece that helps seal that connection.

  3. #3
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Water pump tube is brand new. Never ran the water pump without being submerged in water. The pump has the new grommet and is sealed properly. Water pressure is right on spec. The port side does a times run hotter, but not all the time. Idling at the dock both sides are right at 145 degrees. I have dual temp gauges, one in each head. Water pees out both thermostats equal.

  4. #4
    Join Date
    May 2015
    Location
    PA
    Posts
    4
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    What is the temperature of the pisser water? Is it both heads or just one? It does sound like the poppet, pull that apart and double check to make sure it is not sticking. Do you have the factory the manual for it? If not i could send it to you, I had the black max years ago and I have an electronic version


    Quote Originally Posted by jdewaard View Post
    Water pump tube is brand new. Never ran the water pump without being submerged in water. The pump has the new grommet and is sealed properly. Water pressure is right on spec. The port side does a times run hotter, but not all the time. Idling at the dock both sides are right at 145 degrees. I have dual temp gauges, one in each head. Water pees out both thermostats equal.

  5. #5
    Join Date
    Sep 2001
    Location
    Pekin, IL
    Posts
    9,770
    Thanks (Given)
    502
    Thanks (Received)
    700
    Likes (Given)
    2816
    Likes (Received)
    4463
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    Pull the poppet and make sure the seat is not following the poppet. They are staked in place and I have seen them come loose. When this occurs the poppet will not pass water.

    Rock
    Team Junk

    No sparkling wiggles in here, only dump truck grinches.

    "Screamin Heathen"

  6. #6
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks kinobe. I do have the factory manual. I have not check the temp of the pisser water. It idles at 145 degrees forever, as soon as I accelerate (even just cruising at 2500 RPM) the temp rises. I just don't think the poppet is opening letting enough water flow through the block. Both sides get hot. I have an alarm sender in each head and dual temp gauges. I don't believe it is a blockage, I just think it is not flowing enough water through the block when under load. Am I correct in thinking that the water flow should be a lot more when under load? That is why the poppet open to increase the amount of water flowing through the block?

  7. #7
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks rock. I am planning on pulling the poppet apart this coming weekend. Do it make sense that if the poppet is not opening under load it would cause overheating? In my thinking, if the poppet doesn't open then the thermostats will not let enough water pass to cool the motor under load.

  8. Thanks 85charger thanked for this post
  9. #8
    Join Date
    May 2015
    Location
    PA
    Posts
    4
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    YES, that s what the poppet is for, over a certain psi it opens to allow free flow for cooling, like Rock suggested pull it and double check it as it sounds like it is not operating properly. Secondly, you say it stays at 145 at idle, it should cycle with the tstats, make sure they are working properly as well.


    Quote Originally Posted by jdewaard View Post
    Thanks kinobe. I do have the factory manual. I have not check the temp of the pisser water. It idles at 145 degrees forever, as soon as I accelerate (even just cruising at 2500 RPM) the temp rises. I just don't think the poppet is opening letting enough water flow through the block. Both sides get hot. I have an alarm sender in each head and dual temp gauges. I don't believe it is a blockage, I just think it is not flowing enough water through the block when under load. Am I correct in thinking that the water flow should be a lot more when under load? That is why the poppet open to increase the amount of water flowing through the block?

  10. #9
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by kinobe View Post
    YES, that s what the poppet is for, over a certain psi it opens to allow free flow for cooling, like Rock suggested pull it and double check it as it sounds like it is not operating properly. Secondly, you say it stays at 145 at idle, it should cycle with the tstats, make sure they are working properly as well.
    It does cycle some. At idle the water temp climbs to 145 and then the stats open. It then stays steady between 140 and 145. The stats are brand new and I tested them in hot water with a thermometer to see if they were opening at the proper temperature.

    Has anyone ever had a brand new poppet valve not work properly? Can the spring be too strong? What would cause the binding?

  11. #10
    Join Date
    Jul 2012
    Location
    Lakeville Ma.
    Posts
    220
    Thanks (Given)
    0
    Thanks (Received)
    0
    Likes (Given)
    0
    Likes (Received)
    0
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Did you change the poppet seat? Just thinking maybe it is swelled and binding poppet plunger.

  12. #11
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by s10gto View Post
    Did you change the poppet seat? Just thinking maybe it is swelled and binding poppet plunger.
    Poppet seat, seal, spring, gaskets, diaphragm, cover, and poppet valve all brand new. I'm going to buy all new parts and pull it apart and replace everything again.

  13. #12
    Join Date
    Jan 2002
    Location
    TX......somewhere?
    Posts
    6,455
    Thanks (Given)
    4
    Thanks (Received)
    360
    Likes (Given)
    154
    Likes (Received)
    1048
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    is this a "new to you" complete motor and or just powerhead or have ya had it for awhile and this just started?

    do you have a pressure gauge at all? if so what's it sayin.?
    Last edited by tlwjkw; 05-18-2015 at 11:09 AM.

  14. #13
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by tlwjkw View Post
    is this a "new to you" complete motor and or just powerhead or have ya had it for awhile and this just started?
    Complete motor, new to me. The motor was completely gone through by myself. Alot of new parts and gaskets. I went through everything and replaced all the water related parts (water pump, poppet, and thermostats). Pulled the heads and checked everything, new head gaskets. Pulled the exhaust plate and checked everything, installed with new gaskets. Exhaust adapter plate completely cleaned and installed with new gaskets on mid-section. New exhaust can and gaskets.

  15. #14
    Join Date
    Jan 2002
    Location
    TX......somewhere?
    Posts
    6,455
    Thanks (Given)
    4
    Thanks (Received)
    360
    Likes (Given)
    154
    Likes (Received)
    1048
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    water pressure??? when ya split tha adapter did you physically match tha new gasket to tha old gasket between tha 2 pieces?.....

  16. #15
    Join Date
    Sep 2012
    Location
    Grandville, Michigan
    Posts
    525
    Thanks (Given)
    0
    Thanks (Received)
    5
    Likes (Given)
    0
    Likes (Received)
    9
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by tlwjkw View Post
    water pressure??? when ya split tha adapter did you physically match tha new gasket to tha old gasket between tha 2 pieces?.....
    No, is there a possibility that the gasket is causing this. I know that the hole for the poppet dump was not covered. I did check the gasket when I installed it and all the passages were open. Old gasket was destroyed when the plate was split.
    Last edited by jdewaard; 05-18-2015 at 01:44 PM.

Page 1 of 6 1 2 3 4 5 6 LastLast

Posting Permissions

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