Problem with 15 hp Mercury 4 stroke

[codman]

My mercury 15hp 4 stroke won,t pump water ,whilst in neutral gear .When put into forward drive it flows fine out of the hole at the engine head .Does anyone know what to do to fix the problem ? I have fitted a new propeller shaft as last one was bent .Impeller and gaskets look fine .It start first pull .

 

[TOHATSU GURU]

Re: Problem with 15 hp Mercury 4 stroke

The gear position is not relevant to the pumping. It sounds more like you have an RPM difference where in gear you have more RPM available to the pump. That could be a pee tube stoppage at low RPM or a worn water pump system.

 

[codman]

Re: Problem with 15 hp Mercury 4 stroke

Yesterday I went to start my outboard ,after firing up with choke on it just wouldn,t take any throttle .Do I have a dirty carb? and will cleaning out the float chamber help .Both plugs were very wet with fuel ,and the engine seemed to be flooding .I,ve installed new plugs today but that hasn,t helped .The engine started but won,t rev ,it pumps water fine and there are no blockages in fuel line .Any ideas ?