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Merc 160 over heats above 2000 rpm

D

dminoggio

New member
"Hey guys,
I just replaced th

"Hey guys,
I just replaced the complete water pump,in my Merc 160 outdrive.Housing, gaskets, and impeller. I also replaced my exhaust riser, and checked the saltwater tubes in my heat exchanger for buildup. the tubes were clear. Replaced the thermostat with a 160 degree unit and replaced the freshwater antifreeze. My problem is that the engine still overheats with a load above 2000 rpm. It cools down fast when I slow the engine down to about 1500 rpm. I seem to have a good stream of water on the input side of the heat exchanger coming fro the outdrive, and a good flow of water coming out of the manifold. Any suggestions ????? thankyou in advance for your reply !!!!! Dave"
 
"dave;

Here is a list of th

"dave;

Here is a list of the usual overheating suspects:
-pump impeller and/or housing bad; insufficient water flow
-leaking water pump to water pipe coupler; coupler not fully sealed
-foreign object in inlet hose or T’stat housing (such as impeller pieces)
-kinked hose between drive leg and transom assembly
-collapsed, blocked or kinked hose, blocked PS or oil cooler, etc
-T'stat stuck, partially plugged, or missing
-bad circulation pump or belt
-plugged exhaust manifolds or risers
-plugged check balls in T fitting lines to risers (where equipped)
-salt and/or corrosion encrustation or other blockage in block, heads, manifolds, risers, hoses, or heat exchanger (if equipped)
-bad exhaust flapper causing higher pressure in one riser than the other, and causing discharge water to preferentially flow to the other riser.

Some of the above may not apply to your 160.
You should get an infra red heat gun and see if it is actually overheating. You may have a bad gauge or sender.

Rod"
 
"without seeing,my guess would

"without seeing,my guess would be circulating pump.If you have a good water flow from the drive thru the manifolds and released....then I would think its the antifreeze not getting cooled enough at higher temps when the rpm's increase.As friendly Rod said....check the Tstat and its housing also for obstruction of flow.....Todd"
 
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