Merc 90 Straight 6 1983 Blue Band No water from Tell-tail

[Booze]

Overheating problem tried new impellor still no water from tell-tail. Took of casing and cleaned and blew through with compressor still no joy. Any ideas ?

 

[Vlad D Impeller]

Re: Merc 90 Straight 6 1983 Blue Band No water from Tell-tail

Did you turn the drive shaft clockwise as you pushed the water pump cover down?<br /><br />that way the impeller vanes would be rotating the correct way.

 

[emckelvy]

Re: Merc 90 Straight 6 1983 Blue Band No water from Tell-tail

Does not matter, even if he turned it the wrong way.<br /><br />The blades on a new impeller are plenty flexible enough to turn themselves the right way once the motor is running.<br /><br />What were the symptoms of overheating? Are you sure it actually overheated or did you just not see water coming from the tell-tale?<br /><br />You should see water coming out from around the prop when running the motor on a flusher. This water should be warmer than the flushing water going into the motor. This is good indication of water flow in the absence of a tell-tale.<br /><br />Also feel the exhaust cover on the side of the engine, if it's more than just barely warm you don't have enough water circulating thru the motor. It should be quite cool at idle.<br /><br />If you still don't get indication of water flow, you can drop the lower unit and blow air up the water tube to check for blockages in the powerhead.<br /><br />Also hook a water hose to the water supply tube and see what happens. This eliminates any problems from the lower unit.<br /><br />If you still don't get water thru the powerhead after trying the above, re-post and we'll get to the bottom of it.<br /><br />HTH and G'luck............ed

 

[Elmer Fudge]

Re: Merc 90 Straight 6 1983 Blue Band No water from Tell-tail

If the poppet valve is stuck open for any particular reason water will exit the block prior to reaching the pee hole.<br /><br />Did you reinstall the drive key?<br />The impeller will not turn without it.<br /><br />If all of the impeller vanes are not facing in the same direction, water will not adequately be pumped to the engine block.<br />Sometimes rotation will correct this, sometimes not due to idiosyncrasies and scarring in the pump housing.

 

[emckelvy]

Re: Merc 90 Straight 6 1983 Blue Band No water from Tell-tail

When the motor is at speed, the blades are not even touching the pump housing and the impeller is acting as a circulating pump (vice a positive-displacement pump at low speeds).<br /><br />New impeller blades will certainly turn themselves around in short order. Especially Merc Inline blades, which are very short. This is not the problem.<br /><br />However, it certainly wouldn't pump water without an impeller key!<br /><br />And no Inline 6's were built (to the best of my knowledge) with a poppet valve or even a thermostat. Probably would idle a lot better if they had one!