mercury 1980 9.9 telltale not shooting water

[rodipb]

changed inpeller twice runs for 15 mins and over heats. not much of a machanic can't figure it out. runs great when running

 

["G"]

Re: mercury 1980 9.9 telltale not shooting water

You changed the impeller twice for what reason? Did the impeller go bad both times? An impeller run dry will not last very long. and it will score the pump housing if it gets real hot. Are you installing the key correctly?

Be sure you assembled the lower end to the exhaust housing correctly too. A classic mistake is not getting the water pick up tube in the pump housing.

There is the possibility impeller parts/pieces are in the water jacket. Buy yourself a manual and learn where water goes after the water pump. Learning basics will help you learn how to fix mechanical problems like this.

 

[emckelvy]

Re: mercury 1980 9.9 telltale not shooting water

It's very common to have a problem with the water tube rubber grommet which seals the upper end of the water tube against the powerhead. The rubber swells with salt deposits and squeezes shut the water tube. There's a plastic washer atop the grommet that can distort and impede flow. A replacement with different material that won't distort is available.

Unfortunately the only way to fix this sort of problem is to pull the powerhead.

With the lower unit off, try blowing air up the copper water tube (or connect a source of water to the tube). See if you get free-flow thru the tube. You should feel air blow out the telltale as well as lots of air coming back down the center section.

If you don't, something in the powerhead is plugged. Removing the cyl block cover (over the spark plugs) will allow a check for silt/debris/busted pump blades. If there's no flow after cleaning out this area you need to pull the powerhead.

I even had one motor where the discharge side of the block was plugged. In that case, a lot of water pressure out the telltale but that was the only place water could get out. Very strange, but after fixing all that it ran normally.

HTH & let us know what you find............ed