overheating on merc3.0 L 140 horsepower

[galaxy225]

my boat is not in the water yet...i put muffs on lower unit and let water flow.. started it up...and she starts to get very hot...i did not see any water flowing on the 2 hoses that go from thermstat houseing 1 on the left the other on the right...no water<newbie stick with me here> would like to know what i should to fix...i dont think there was water flowing from that hose that goes to lower unit either.....thanks please help

 

[hondon]

Re: overheating on merc3.0 L 140 horsepower

Start with the water pump in the sterndrive.If you just got this thing and don't know when it was last changed then it is time. If you do know and it's been more than a couple years then it's time. If you have been cranking and cranking on this thing to get it going then it's time.Get the picture.

 

[kdmiller8251]

Re: overheating on merc3.0 L 140 horsepower

Galaxy: Arent you the guy who bought the boat that was sitting for 2 years??? If so I would also pull apart the thermostat housing and check in there... I bet you have a ton of rust.....<br />Chances are at this point you may have problems with your impeller in the lower unit.....<br />I bought a boat that was sitting for a few years and have overheating problems also... I have replaced all pumps and impellers and thermostat and am having the problem still at high speed.. I am working on correcting it... But there is a ton of rust and build up in the thermostat housinng, manifold and probably risers that I have not gotten to... Beware.... and good luck<br /><br />Tallman

 

[galaxy225]

Re: overheating on merc3.0 L 140 horsepower

thanks tall man any body else how gave some helpful info......i am going to change the parts in pump tomorrow.....and clean all the other parts like manifold and thermastat housing....

 

[Boatist]

Re: overheating on merc3.0 L 140 horsepower

The hose from the left side of thermostat is water from the impeller in outdrive. If no water then impeller is bad or no water getting to it. You should have muff over holes just above the prop shaft and below the cavitation plate. If no water sounds like impeller to me.