90 hsp Mercury water pump issue

Discussion in 'Boat Repair Help' started by Boomer, Jun 27, 2009.

  1. Boomer

    Boomer New Member

    Messages:
    1,037
    State:
    Oklahoma
    I have a 2003 90 hsp Mercury motor, the last 2 times I have been out in my boat, the water pump will not work on initial start up, but after about 5-10 minutes will start pumping?

    Anyone have any suggestions? I am baffled, we went out last night, got the boat off the trailer, the pump wouldnt work, so we used the trolling motor, in the morning, we came back in and trolled up to the ramp, then kicked on the Mercury let it run about 10 minutes, then it started working?
     
  2. Stubby

    Stubby New Member

    Messages:
    208
    State:
    Kansas, Ar
    I hope someone gives you an answer on this Boomer, I got a 1995 40hp Merc doing the same thing only not quite as long. maybe 2 minutes. I was going to post in Bubbas Outboards but we may get the answer here. My machanic says it is because the engines drains itself between starts like as if there is no thermostat or check valve to hold any water in the block. good luck!!!
     

  3. Boomer

    Boomer New Member

    Messages:
    1,037
    State:
    Oklahoma
    You know I didnt think about that. Maybe it is like it needs to flush the air out before it will start pumping. I put the Mickeymouse ears on it prior to taking it out, but it still would not pump.

    Hopefully someone will clear this issue up for us. If I dont get any response I will post it on Bubba's.
     
  4. mdavis

    mdavis New Member

    Messages:
    139
    State:
    Iowa
    I would suggest maybe changing out your thermostat; cheep fix and have a feeling it is not reading the water temp correctly.
     
  5. AwShucks

    AwShucks New Member

    Messages:
    4,532
    State:
    Guthrie, Oklaho
    I would say the thermostat is not opening at the correct temperature. But, don't let the engine run until you hear the audible alarm... it is too late then. I've been installing water temp gages on my Evinrudes, fairly easy to do.