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470 mercruiser over heating problem

C

cynandcap

Member
"I just Bought a 1980 EBKO w/4

"I just Bought a 1980 EBKO w/470 mercruiser 170 hp
at a idel it seems to be fine at higher speeds it
over heats .
I replaced the impeller , flush the system
replaced the heat exchanger Pulled off the exhust
manifold and it seems to flow ok replaced the t stat.
any more suggestions????"
 
Is it overheating or just runn

Is it overheating or just running hot? What are the Temps? I had a similair problem with my 470. Gauge was reading wrong temp. There are 2 spots next to each other to install sending units. I put in a mechical gague which did read normal temps (160-170). Installed new electric sending unit and gauge-now all is well
Chris
 
Is it an internal water pump b

Is it an internal water pump because their is no belts and when it get hot the temp gauge gets 200 to 240 and the water in resivor is boiling???

craig
 
"The engine water pump is bolt

"The engine water pump is bolted directly to the camshaft - very unlikely it is bad. Better be careful - if you get that hot you can start seeing mechanical damage. Check your timing, pull your freshwater hose at the exchanger to make sure you have water moving, check your coolant level and make sure no air is trapped in the system. There are a lot of previous posts on this engine - might look through them. Should run about 160-180 degrees. As Fastjeff always says, "Go buy a laser temp gun." I've been using one for several years and it is very handy. It will tell you if you are really running at 200 degrees."
 
"You may have a 3 inch heat ex

"You may have a 3 inch heat exchanger. Later 470's were supplied with a 4 inch, you may want to consider an upgrade to larger exchange. How is the exhaust elbow? If it is partially clogged it will block the raw water flow.
Chris"
 
I Have upgrade to 4" heat

I Have upgrade to 4" heat exchanger and the exhaust elbow and manfold i have taken off and flush water through it and it seems to flow ok.

craig
 
"Craig, this is a tuff one for

"Craig, this is a tuff one for you. It seems you have gone over all the basics. You mentioned boiling?, could it be air getting into the cooling system from a blown headgasket? Does the coolent level stay constant? My engine did run hot at high RPM's, but it was fixed when I changed the outdrive impeller. 2 blades on it were missing. The water flow now is excellent. If I run on the muffs around 1500 rpm, it sucks all the water my garden hose can supply, which is ALOT! I;ll try to supply a pic for you to compare. My engine never goes above 180 even with a 3 in exch. Perhaps its time to bring in someone with experience to take a look. The 470 has an iron head with aluminum block, if you keep overheating it, you will most likely blow a headgasket or worse. Good luck, let us know how you made out. You could try posting at the breezeworks forum, its dedicated to the 470. Good Luck
Chris
http://www.breezeworks.net/cgi-bin/MBoard/forum/display_forum_topics.asp?ForumID =1&PagePosition=1&ThreadPage=1"
 
"CRAIG THIS PROBLEM YOU ARE HA

"CRAIG THIS PROBLEM YOU ARE HAVING IS INDEED A HEAD GASKET. I HAD THE SAME THING HAPPEN TO ME ALONG WITH A TON OF OTHER THINGS AND I KNOW THIS ENGINE VERY WELL. MY OVERFLOW WAS BOILING AS WELL AND IT WAS OVERHEATED WHICH CAUSED THE HEAD TO WARP, THEN I HAD TO REPLACE THE HEAD BECAUSE IT ALSO CRACKED. MAKE SURE YOU HAVE A PRO CHECK THE HEAD OUT BEFORE YOU REINSTALL IT AND CHECK YOUR CYLINDER WALLS TO MAKE SURE THEY AR NOT SCORED, THESE ENGINES ARE A PAIN BUT WHEN YOU KNOW HOW TO TAKE CARE OF THEM THEY RUN GREAT AND ARE FUEL EFFECIENT TO TO BOOT. GOOD LUCK
VIC"
 
Thankyou guys for all the advi

Thankyou guys for all the advice.
What i have found out is theire was a automovtive
t stat. i replaced it with a marine t stat
it ran better at higher speeds but a lower speeds it would heat up to 190 to 225 i need some more ideas.

Thanks Craig
 
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