Merc 470 cooling issue

[rustypenny]

Hi - I have an '82 mercruiser 470 w/a closed cooling system Recently, it was driven into shallow water and the lower unit was in sand for a minute or two. Shortly thereafter, the hose that goes from the intake manifold to the exhaust manifold blew a hole. I replaced it. The next time on the water, while idling, started to smell burning rubber and then the hose from the Intake Manifold to Water Pump blew. Temp gauge wasn't moving at all prior to the last hose blowing.

Did the sand plug something?

How does the raw water cooling system work vs. the closed cooling system?

Thanks for any suggestions you may have!!

 

[b_ry]

Re: Merc 470 cooling issue

yeah definately sand plugged it up, probably have the heat exchanger full. http://outdrivetools.com/overheating_highspeed.html check this site out they can tell you possible ways to clean it out. i cleaned the heat exchanger on my 470 and it had a bunch of sand in it and i never even hit a sand bar. i would start there. possibly plugged up exhaust elbow the water probably couldnt flow so it had to come out somewhere.

 

[Bondo]

Re: Merc 470 cooling issue

Ayuh,... The sand probably Destroyed the Impeller,... Change it...

 

[rustypenny]

Re: Merc 470 cooling issue

Okay thanks, I'll take a look. How did you clean yours?

 

[rustypenny]

Re: Merc 470 cooling issue

Are you referring to the circulation pump impellar located on the front end of the camshaft?

 

[Bt Doctur]

Re: Merc 470 cooling issue

The one in the lower unit of the outdrive

 

[rustypenny]

Re: Merc 470 cooling issue

Okay, thanks again.