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Water pump shot

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fuzzywuzzy

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"I have a 40 HP Mercury Classi

"I have a 40 HP Mercury Classic, 4 cyl, SN C160782. Once before this season, and this afternoon when I tilted the motor up to miss some rocks the water flow out of the engine was replaced by steam. After two tries of about 30-45 seconds to restore the water flow, I shut it off and used my trolling motor to return to my dock. Before, the flow returned when the engine was cool, I assume it would as well this time. Is my pump shot? Should I replace the thermostat at the same time? What temp is the thermostat supposed to be?"
 
"If you have to ask about repl

"If you have to ask about replacing the impeller - it is probably "overdue" - every second year regardless of whether you run it a 1000 hours a year or it sits in the yard.

Unless I'm remembering incorrectly, I do not believe that your model has a thermostat - JB would probably know for sure. Yours is one of the 4 cylinder models - correct?

Also, check for blockages, bad seals at the waterpump itself (not the base seals for the lower unit).

Merc usually has 3 (levels) of waterpump kits - 1 is simply the impeller and a gasket, the next up contains cover seals etc (the one I most often use) and then the 3rd contains base seals etc which will help if you have water in the lower unit. Of course the cost escalates as you move up to the more thorough kits..."
 
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