Volvo Penta 5.7 GI-F (2006) water in Cylinders

[sdarbyj]

Took the boat out for the first time this year. Stopped (slowly with engine running) a couple minutes after warming up to start wakeboarding. When we went to start it back up the boat wouldn't start. Found out there was water in both cylinder banks Cyls 3 and 6 had the most. Pulled the plugs and impellor, got all the water out checked the crank case oil, replaced plugs and started and ran the boat for a few seconds.
Compression tested all cylinders were 150 - 155.
Then I pulled the plugs and fogged the cylinders.
After that these still does not appear to be water in the oil on the dipstick (all fresh oil). I haven't opened the filler cap, yet I heard this is also a good check for milky oil.
I did pull the risers and exhaust manifold and they appear to be ok they held standing water without leaking, but I don't know how to pressure test them.
I am wondering if it is the intake manifold but was wondering if there was a way to test it on the boat?

 

[alldodge]

Assume your if fresh water, and if so your exhaust is probably fine

VP done away with exhaust flappers and in this case it probably could have saved the motor.

Wake boats take on all that water to make them heavier. The heavier they get the low in the water they go. Backing up with all the weight is probably what made it happen

Don't know if you have room to add maybe 3 to 4 inch risers between manifold and elbow. If you have the room this would help stop this kind of thing in the future

 

[Lou C]

VP does sell several sized taller exhaust elbows however I’m not sure that everything will line up on the original Y pipe, I never agreed 100% with their decision to remove the flappers. I have the exact same flapper design on my Cobra (which VP adapted for the SX) and never had water in the cyls from launching or slowing down. I suggest that you measure the static water line of the boat & see if you need taller elbows. Should be above 13”.
Another idea is to remove the exhaust bellows & install an exhaust flapper like those used on inboard boats with thru the transom exhaust.
I just didn’t see the sense of removing the flappers without even telling the owners to measure the static water line.

 

[sdarbyj]

I do not think it was weight or related to how the boat was driven. No extra ballast. We have done the same thing for years.

I’m wondering if it was a failure of the water passage in the intake manifold and if there is a way to test that on the engine. Maybe remove the thermostat housing and add water with the plugs out?

 

[sdarbyj]

There was one difference on the boat this trip. My boat has a hose connection by the engine. I had run the boat off the hose at the house for 10 minutes before going to the lake. But I forgot to plug that hose.

 

[Scott Danforth]

I never agreed 100% with their decision to remove the flappers.

remember, the VP drives of that era had a flapper on the exhaust exiting the drive on the AV plate.

 

[Lou C]

I do not think it was weight or related to how the boat was driven. No extra ballast. We have done the same thing for years.

I’m wondering if it was a failure of the water passage in the intake manifold and if there is a way to test that on the engine. Maybe remove the thermostat housing and add water with the plugs out?

The intake manifold can rust out below the thermostat housing (this would be more common in salt water areas, probably uncommon in freshwater), but that will put water directly into the motor oil right in the cam valley below the intake manifold, not in the cylinders.
How old are the manifolds & exhaust elbows? Any sign of rust trails from the joint between them? Volvo revised that gasket a few times, it was a known issue.
Ever measure the static water line of the boat? With no exhaust flappers it is particularly important. Some boats need taller exhaust elbows due to inadequate static water level height (the height of the exhaust elbows above the water line in the exhaust Y pipe, should be 13" or more).

 

[Lou C]

remember, the VP drives of that era had a flapper on the exhaust exiting the drive on the AV plate.

They had those on the AQ style drives, but not on the SX style drives IIRC. The SX style drives had an exhaust bellows similar to the OMC Cobra because the whole OMC transom mount/gimble assembly was adapted from OMC's original design.

 

[Lou C]

Cyls 3 & 6 are basically right under the area were the gasket for the joint between the manifold and elbow is.

 

[sdarbyj]

Maybe it was the gasket between the riser and manifold. I went to get a picture of the part number and noticed places that looked like the seal was compromised.
It looked better the day I took it off

 

[Lou C]

You can’t really tell till it’s all cleaned up, I would dress the surfaces with a mill bastard file & check for flatness with a straight edge & feeler gauges. I think Volvo says less than .003” variation. Get the Volvo OEM gaskets & follow their instructions.

 

[sdarbyj]

I pressure tested the manifold. I figured out how I might be able to test the riser. But I think I may just buy new risers. One had a small bump in the exhaust chamber and it looks like the water jacket dips in there on the other side. You can see it in this picture. Also both risers water jackets were almost clogged with scale.
I’ll try to call the boat shop today but is there a cross reference for Volvo part numbers. I haven’t been successful looking up the number that is stamped on my riser.

3863479

 

[Lou C]

Barr Marine makes aftermarket versions of those

 

[sdarbyj]

Saw another thread on here about that being the casting not the part number

 

[cptbill]

Where the gaskets that were between the riser and the manifold the original metal ones?,

 

[sdarbyj]

I believe so.

 

[Donald0039]

Exhaust manifolds and exhaust elbows/riser are cheap until you get to ones with a catalytic converter. So if any concern with how thick the metal is for the water jacket is replace.

 

[Lou C]

I recall it being mentioned on here that Barr Marine casts the parts for VP, no reason to pay extra for VP IMO. I installed my in ‘17 they are still holding up well & will prob replace the elbows this fall.

 

[cptbill]

Those metal gaskets have been known to fail, if you still have them check the real good

 

[Lou C]

When I installed mine (Barr gaskets) I used Permatex Aviation as recommended by the Barr tech guy & no leaks after 4 seasons of use….