Welcome Guest - Sign Up today
Welcome Guest - Sign Up today


No announcement yet.

No Water from Tell Tale at Idle

  • Filter
  • Time
  • Show
Clear All
new posts

  • No Water from Tell Tale at Idle

    I have a "new to me" 2002 Mercury 150 2 Stroke. The motor visually looks almost brand new. It hasn't been run in about 10-12 months. When I got the motor, I changed the water separator and fuel filter. I replaced the entire water pump and impeller. When I start the motor, I get no water from the tell tale, but do get water out of the prop and upper exhaust port. When the motor RPMs are raised slightly, water starts to flow from the tell tale. It will run fine and water is flowing for as long as I want it to. But as soon as it returns to idle, the water stops flowing from the tell tale. I have read several theories on the internet that say either, water not flowing right away is normal, some say it should flow a second or two after starting. Then there is the tell tale is down stream from the thermostats theory, which makes sense to me, kinda. If the water doesn't flow until the tstats open, then why when it returns to idle, does the flow stop? The tstats should remain open if the motor has been running above idle for 20 minutes, right? I dont have a water pressure gauge, but the thermostat never goes over 140. However, I have not verified if the thermostat is giving accurate readings.

    Does anyone have any tips or advice weather this is normal, or what I should or could check to make sure everything is working?

  • #2
    I don't have any experience with motors that "new" (most of mine I worked on 1970-1998) but in general they all work on the same principal .

    If there's no obstruction in the Tell-tube and in the power-head (you can verify by poking with some picture frame-wire to see if debris comes out)

    The Water-pump (when properly below the water-level) will produce enough pressure to pump the water all the way to the top of the head and ultimately coming out of the tell-tale at cranking-speed.

    It may take 20 to 30 seconds of cranking to get that, but it will.
    the thermostat does not close-off the water circulation completely, actually very little and the majority of the return water flows through the exhaust-plate to prop not even through the thermostat (at least on my older motors)

    I hate to think; there's a leak/obstruction between the water pump-gaskets/tube/housing causing not enough pressure being built up at idle-speed.

    the only way to verify is to check for obstructions in the tell-tale and/or fitting going into the power head if that's good.......pull the lower-unit and check if everything is right/no leaks when rotation shaft/no obstructions like collapsed o-rings/rubber sleeves.

    let me know
    working on 1990 force 90 horsepower Engine serial. 17523 Engine model. 906X90B


    • #3
      Sign up today
      its jus fine... no worries unless ya get tha over temp buzzer goin'.