Water in Oil

[ajgaines]

The previous owners of my Catalina 30 had backflowed the exhaust water into the cylinders and destroyed the A4 that way.

I bought a rebuilt A4 and installed it and finally have had the chance to use the boat a bunch the last couple of months. I found that I was having issues with my RPMs only going up to about 1300 and after I wasn't even able to fight a breeze to get out of my slip I decided it was finally a problem.

I found water in the oil once again. I have religiously closed the seacock when cranking and really don't know how the water got in there. Perhaps it is just because of the small amount of clearance from where the raw "used" water enters my hot section of the exhaust? With the Catalina 30 there's really no space to put it any higher.

Anyone have any suggestions?
One thing I was thinking was to install the closed fresh water system but the fresh water cooling system that moyer sells would not fit either as there is no clearance behind the flywheel for the 2" required.
I had also changed out the entire exhaust hose portion of the exhaust but it still has the old muffler. Is there something in the muffler itself that could be backing the water up?

[Dave Neptune]

The water can also get in through a pin hole in the manifold which luckily is an easy check and a not so cheap fix. An exhaust issue may require some tweaking of the system you have. I doubt your system is still stock and we have a few Cat 30 guru's on this site for excellent guidance.

Dave Neptune

[Dave Neptune]

Pt II

Did you check the anti-syphon valve in the cooling loop?

Dave Neptune

[edwardc]

A fresh water cooling system (FWC) will not help with an exhaust water reflux problem as the FWC system still uses raw water to cool the exhaust.

I know the Catalina's are severely height limited, but every little bit helps. The farther and lower the water injection point is, the better. On my original engine (not in a Catalina), the exhaust elbow had NO riser!! A simple 90 degree turn downwards, with the water injected right in the elbow! Spray and steam could (and did) migrate back into the manifold.

Ideally, you want the water injection point to be at least 4" lower than the bottom edge of the exhaust opening on the manifold, with as much lift (even an inch!) as possible between it and the manifold. And an anti-siphon valve in the water injection path is a must. Put it at the top of a hose loop, placed as high as you can inside the cabinetry.

[ndutton]

Catalina 30 guys beware

In addition to the latest Moyer Marine Newsletter, An Exhausting Problem, the Catalina 30 has some serious exhaust system design challenges, particularly the style of waterlift muffler combined with the low rise hot section. Using the Centek line of waterlifts as an example, a side inlet muffler (as opposed to a top inlet) introduces a significant backflooding risk while heeled. The attached drawing shows both types on an even keel and under 15° of heel, sloshing under way not included. The blue dashed line represents the typical residual water level inside the waterlift muffler after engine shutdown. As can be seen, the side inlet greatly reduces the usable, backflood preventing volume of the muffler.

[ajgaines]

Did you check the anti-syphon valve in the cooling loop?

Dave Neptune

I know it has one. How do I check that it is working?

[ajgaines]

A fresh water cooling system (FWC) will not help with an exhaust water reflux problem as the FWC system still uses raw water to cool the exhaust.

I know the Catalina's are severely height limited, but every little bit helps. The farther and lower the water injection point is, the better. On my original engine (not in a Catalina), the exhaust elbow had NO riser!! A simple 90 degree turn downwards, with the water injected right in the elbow! Spray and steam could (and did) migrate back into the manifold.

Ideally, you want the water injection point to be at least 4" lower than the bottom edge of the exhaust opening on the manifold, with as much lift (even an inch!) as possible between it and the manifold. And an anti-siphon valve in the water injection path is a must. Put it at the top of a hose loop, placed as high as you can inside the cabinetry.

It allows about 1.5" under the cabinet. I guess it would be possible to try to figure out a way to build a higher hot exhaust up into the cabinet and take out the bottom drawer, but maybe that would risk fire? I haven't seen anyone else that's done that

[ajgaines]

In addition to the latest Moyer Marine Newsletter, An Exhausting Problem, the Catalina 30 has some serious exhaust system design challenges, particularly the style of waterlift muffler combined with the low rise hot section. Using the Centek line of waterlifts as an example, a side inlet muffler (as opposed to a top inlet) introduces a significant backflooding risk while heeled. The attached drawing shows both types on an even keel and under 15° of heel, sloshing under way not included. The blue dashed line represents the typical residual water level inside the waterlift muffler after engine shutdown. As can be seen, the side inlet greatly reduces the usable, backflood preventing volume of the muffler.

I see. Mine has the fiberglass muffler with the in and out both on the top. I had to refiner glass it a little but it seems to be as big as the mufflers get for retaining water

[ndutton]

Top in - top out is the point I was trying to drive home for the Catalina 30 and other boats with engines similarly situated. Can you provide pictures of your hot section and water injection? Maybe we'll see something. Pictures of mine (also a C30) are attached.

Does your exhaust hose have a check valve inside the port cockpit sail locker? You mentioned your anti-siphon has a valve. You might consider a vented loop instead.

[Dave Neptune]

I had an E35MKII which has the same style installation. I cut a couple of holes in a shelf that ran under the toe rail inside. Although it was on the port side it was as high as I could get it and not have it outside somewhere. Raising the anti syphon really helped for my installation. Getting it as high and close to centerline is best. I had no problems on starboard tach when it was at it's "lowest" however I did not have it in any extreme weather keeping her really heeled over.

Checking the valve is quite simple. Once the valve and loop are removed the integrity can be checked by simply plugging one end and sucking and blowing on the other. It should hold when you blow and release when you suck on it, not rocket science . It is nothing but a check valve and personally I replaced mine every 4~5 years rather than cleaning because I had so little "rise" available above the engine since we too sat on it inside the boat.

Neil will probably have a good idea of where to mount the valve on your Cat 30 as he has a really nice one, and I do mean really nice!

Dave Neptune

[ajgaines]

Top in - top out is the point I was trying to drive home for the Catalina 30 and other boats with engines similarly situated. Can you provide pictures of your hot section and water injection? Maybe we'll see something. Pictures of mine (also a C30) are attached.

Does your exhaust hose have a check valve inside the port cockpit sail locker? You mentioned your anti-siphon has a valve. You might consider a vented loop instead.

This is the setup. Looks similar to yours. I couldn't get more clearance without going up out of the engine area, and I'm not sure how I would do that.

What did you use to seal your hot exhaust portion? I would smell a lot of exhaust when running the engine and I believe it was leaking somewhere out of there. I found it hard to set it up quickly so I had to unscrew a few times while screwing it all together

[ndutton]

What did you use to seal your hot exhaust portion?

This is the sealant I used, available at McMaster-Carr. It's rated to 750°

[zellerj]

Water can also get into the engine via the exhaust when large waves hit the stern pushing water back through the exhaust. This happened to me when I was stuck on a sand bar and boat wake slapped the stern on my CAT30. If your slip exposes your stern to wakes or chop this could be the issue. Many exhaust systems have an exhaust flapper on the stern, but they are prone to falling off.

Check to see if your exhaust hose is high in the port lazerette. It should have the high spot close to the bottom of the port cockpit seat.

[ajgaines]

It seems the antisiphon valve isn't working but how would that flood the muffler?

[JOHN COOKSON]

It seems the antisiphon valve isn't working but how would that flood the muffler?

It's the other way. Water in the muffler gets siphoned into the engine. The antisiphon valve breaks the siphon.
As a warm engine cools it can, in some cases, create enough of a vacuum to start a siphon from the exhaust system into the engine.

ex TRUE GRIT