1977 merc 500 cooling

[frwhlr38]

Ok guys i just picked up this boat and motor the motor is a merc 500(50) hp serial #4578459 i put the muffs on the other day fired it up and no water comming out of tell tail cleaned it all up, still no water installed new water pump but before i fire it up i need to know if water will run outa tell tail all the time or just part time i was told there is no thermostat in these engines just trying to check before i fire it off MANY THANKS

 

[Ken G]

Re: 1977 merc 500 cooling

Check the tell tail outlet and hose for obstructions. They are a favorite place for mud dauber nests. You can clear them with a piece of thin wire or heavy monofilament.

 

[frwhlr38]

Re: 1977 merc 500 cooling

Yes i have cleaned the hose out but i wanted to know if it pees all the time or just sometimes MANY THANKS

 

[Ken G]

Re: 1977 merc 500 cooling

Oops, I meant to add that I believe it should pee all the time on muffs. I own the same motor but I haven't ran it in 3 or 4 years. It's on the project list for this winter.

 

[frwhlr38]

Re: 1977 merc 500 cooling

Well ken thats me this is winter project going thru this thing and so this is why i was asking because i dont wnat to put water to it now just to find out

 

[emckelvy]

Re: 1977 merc 500 cooling

Once water is initially pumped up into the powerhead and it fills up completely, the telltale should flow all the time. The stream will increase in strength as engine speed increases.

When you're on the flush muffs, be sure you have enough water pressure to force a bit of water past the muffs while the motor's running. Just a bit, enough to tell that you've got the suction side of the water pump completely flooded with water.

BTW compressed air along with a blow nozzle works real well for unplugging telltale hoses.

HTH...........ed