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2002 volvopenta 81 gic overheating

R

rac

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Displacement (litres)8

Displacement (litres)8.13
(hp)375
Max engine speed (rpm)4600
8.1 Gi-C 3869197 SERIAL 4012084066
This engine is overheating and has been since new acording to the previous owner. It has about 80hrs in salt and 20 in fresh water the raw water pump does not seem to create enough suction to stay primed . New t-stat new impeller manifolds cleaned . Is there a know design problem with this engine?
Thanks Richard Clark
 
"What do you mean by overheat?

"What do you mean by overheat? Normal operating temp on this engine is 180-190 degrees.
This engine is fresh water cooled with a heat exchanger. The issues with this engine are usually installation related.

1) No water strainer: Lets "flora and fauna" plug up the tubes in the heat exchanger.
2) If there is a water strainer, the cover on the water strainer if not properly installed or if the gasket is missing or damaged, will leak air, i.e. suck air into the water stream and overheat.
3) Every once in a while barnacles will grow in the water intake and restrict water flow.
4) Sometimes the engine gets installed with an undersized water hose/inlet. There should be no reduction in the hose size from the water pump all the way to the thru hull.
5) Air leak on the transmission and/or engine oil cooler.
6) Off chance possibility... not enough antifreeze/water mixture on the fresh water side."
 
Thanks for the reply Robert

Thanks for the reply Robert
It overheats to 210 + it is raw water cooled .No heat exchanger . I have found a air leak at the power steering cooler and fixed that .It seems to have very little suction at the pump.
Richard Clark
 
Under what conditions does it

Under what conditions does it overheat?
AT idle...at slow speed... above xxxx RPM???

I had a persistant overheat problem on one of my boats that turned out to be a single barnacle inside the thru hull fitting.

When the impeller was replaced was the old one intact??? Possible undersized (wrong) impeller?
Also...some impellers have a drive key and if its missing...!

Lots of little silly stuff can cause overheating.

Is this an I/O or a straight inboard?
 
I installed a new impeller 6 m

I installed a new impeller 6 months ago .The old one looked fine .I did not replace the sealing ring could this be a problem?(part#827247-8)Also I ordered a 3862567-9 impeller and received a 3862465 I assume they have changed part # .It overheats at idle running and sometimes goes for hours without overheating .Thanks for the help
 
I think Im making some progres

I think Im making some progress. I installed pressure gauges on the suction side and pressure side of the raw water pump. I got nothing on ether side Then I disconnected the pressure hose and got plenty of suction 20# when I blocked the hose . I flushed the engine and manifold with pressure then hooked up the hoses at 3000 rpm about 3# suction and 10# on the pressure side. I ran the engine for an hour and it worked fine . Cranked it back up no suction . I think I have a blockage somewhere between the pump and exhaust . Does anyone know were I can find a drawing of the outdrive plumbing?

Thanks Richard Clark
 
I agree its not an outdive pro

I agree its not an outdive problem .Its running 135 to 140 now . I have a operators manuel a shop manuel and a parts catolog none show much about the outdive the parts book is the most help it shows the break down of most of the engine componats . The water exits were the outdive swivels up and down at the transom I thought it was suppose to come out the exhaust ports
 
Thanks for the help Robert I g

Thanks for the help Robert I guess it was an obstruction that cleared under presure . Seems ok now I just dont have much confidence the problem wont come back .

appreciate the help
Richard Clark
 
"Those water exits at the tran

"Those water exits at the transom are relief ports to minimize back pressure at idle. At anything much above idle, water comes out the exhaust port. At WOT, water flow can be in excess of 50 GPM."
 
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