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aq125b heating up

K

kbcave

Contributing Member
i have a 1985 aq 125b 4cyl volvo motor, at idle speed the engine runs at 180 degrees, at speed it quickly rises towards 240 degrees, slow to idle speed and it goes back to 180...
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this is the first time i have had the boat out, bought it about a month ago. got home and pulled the impeller, looks good, soft pliable rubber. was kind of scrunched up in the housing and i am wondering about the rotation direction of the impeller blades.
 
found part of an old impeller in the heat exchanger. flushing it now, going to clean the hoses and tubes and try to clean and flush the whole sea water system. got the system cleaned, ran water hose directly into intake pipe, dumps a bunch of water out the exhaust ran at 3000 rpm in the driveway, didnt go over 180degrees, took it to the lake, ran 180 at idle all through the 5mph zone, soon as i took it to 3000 rpm temp started rising to 240,, ???? any ideas???
 
Heat exchanger clogged.More than likley the manifold is clogged. Remove it and check the end for blockage.
Flow test it.It should allow as much water in and out as a good hose can give it.
Pics of the end of the manifold??J
 
i have put a water hose directly in the intake pipe and ran the motor in the driveway at 3000 rpm the motor went to 180 and stayed there, so i started investigating the water connection on the lower unit. pulled the unit and found that the gasket was damaged and the bushing completely gone. it seems me that once on a plane it would be sucking air from there instead of water. i have ordered all new bushings, needle bearing and o rings for the water pipe in the lower unit. probably wont get the parts this week but i will post updates when available thanks.kc
 
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