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Volvo Penta 2004 8.1 Gi-EF raw water intake

P

Pinch

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I have a 2004-2005 8.1 Gi-EF with a closed cooling system. According to the service manual the raw water for the heat exchanger is picked up at the water intakes on both sides of the lower gearcase.

On my boat, the raw water appears to come from a thru-hull seacock. Is this a modification or were some 8.1s installed this way? Thanks.
 
Re: Volvo Penta 8.1 Gi-EF raw water intake

el_pescador said:
You can install it either way, depending on your preferences.
Click to expand...

Thanks for the quick response! I think the boat originally got its raw water from the lower gear case and was modified. Right where the raw water hose connects is another hose that appears to come from the transom and it's plugged.

I've heard from a Chris Craft dealer that the boats w/ the 8.1 always come from the factory drawing their raw water from the gearcase. Why would this boat have been modified and is it a kluge fix? This is a late model boat and I I'm concerned as to why this was done and if it's better that the engine/drive are repaired properly and returned to their original configuration.

Do the closed-cooling system 8.1s require a greater volume of water?

Thanks!
 
Re: Volvo Penta 8.1 Gi-EF raw water intake

This is not a kluge fix (if done properly)... I have modified every one of my Volvos (3 since 1964) to have a thru hull pickup... Why?... In the area that I operate my boat in, there is lots of very skinny water, not all of it neatly shown on charts. Having the pickup thru hull reduces the ingestion of sand by the engine when I have "close encounters" and the resultant damage to the impeller on the raw water pump. It also can give you a neater way to flush your engine with fresh water and winterize the engine.

Closed cooling systems generally require a but more water.

See... for plumbing of my raw water intake for my FWC system...

http://home.comcast.net/~rfierro/pwpimages/ThruHull_rawwaterinlet_internal_2266.JPG

The hose bib (see red handle) allows me to flush my engine by attaching a short hose that sits in a bucket with a free running hose also in the bucket... (NEVER NEVER hook the hose directly to the inlet of the raw water pump)


and

http://home.comcast.net/~rfierro/pwpimages/Thru_Hull_WaterInlet_2257.JPG

for the scoop/filter that is over the thru hull inlet on the outside of the hull
 
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Re: Volvo Penta 8.1 Gi-EF raw water intake

Interesting question... never tested it. Next time I have the boat out, I'll see if the raw water inlet line is under pressure or vacuum when boat is running. With the thru leg, it's a vacuum on the run. A bit crude of a test...but!


BTW... it's not obvious in the picture, but the proper orientation of the scoop is NOT facing forward, but "kicked in" towards the keel slightly. Water flow at that point on the hull is not straight fore to aft but rather back and up (outward) at an angle from the bottom of the boat's "V".
 
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Not sure if this particular thread is still active. I have a Penta 8.1 motor with a DPS-A sterndrive. It appears that Volvo does not install (as standard equipment) a seacock on the raw water intake system between the sterndrive intake, the transom, and the water pump on the engine. Is this true? The followup to this is, is there anyway to replace the impellers on the water pump while the boat is in the water??? The same question applies to the engines serpentine belt, which passes "behind" the raw water inlet and outlet lines. It appears even the serpentine belt can only be replaced by disconnecting the water lines (which requires the boat being out of the water because I can't seem to find a seacock)... Am I missing anything? Thank you in advance.
 
Stern drives generally don't come with sea cocks.
Disconnect the inlet hose to the pump and raise its end above the waterline...make sure its well above the actual water level as you sit in the back of the boat... "crew" up front helps. ....or.... stick a cork in the end of the hose.
 
sandkicker said:
Stern drives generally don't come with sea cocks.
Disconnect the inlet hose to the pump and raise its end above the waterline...make sure its well above the actual water level as you sit in the back of the boat... "crew" up front helps. ....or.... stick a cork in the end of the hose.
Click to expand...
Thank you. That's was what I was afraid the answer was going to be. The inlet hose isn't long enough to raise above water line but the cork suggestion (or similar) makes sense.. Assuming this method is just an exercise in doing it VERY quickly as it's a fairly large intake line that will have ALOT of water flowing once disconnected from the pump.....
 
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