Yanmar water lock

Am in Oriental after uneventful 3 1/2 day passage from Manjack to Beaufort this week, Yesterday engine would not turn over, a repeat of the same problem we had last year with water backing up into the cylinders. Am at Deaton’s Yacht Services getting good personal attention from John Deaton and his mechanic. Pulled injectors, got water out, etc. Will almost certainly get her going again and running as smoothly as usual, but the BIG QUESTION is why we are getting this intermittent water lock problem. Engine starts almost instantly down here in the “hot country” so it is not due to extended starter runs pumping water up into the cylinders. So it must be backing up or syphoning from the mixing elbow somehow, Replaced the mixing elbow last year when at Tiger Point in Fernandina, so all of that sustem is new and professionally installed.

But we now have a repeat of exactly the same problem as before we relaced the old elbow, so the problem seems to be a water level versus elbow height or hose length or bad anti-syphon valve issue. Other BCC owners have had a similar problem, Ben Ericson’s “Elizabeth” for example.

I did notice a lot of white smoke first time I started her when I got to Donny’s at Green Turtle Cay last month (where she had been moored since January),it took a much longer than usual starter run before she started. After that all was normal, always starts instantly in warm weather and has been running very smoothly.

Any thoughts?

Ouch! I hadn’t heard about this before, Scott. Thanks for the heads up.

I’ll look forward to learning how you resolve this.

A perception check: am I right in understanding that, after you stop the engine, water is somehow entering the exhaust manifold. And the prime suspect is water from the exhaust, not coolant penetrating from some internal fault in the engine?

If it were engine coolant that was leaking, then your coolant expansion tank would be running low. And your freshwater coolant would be being pressurised with combustion gases. If it were a car engine with a radiator, I’d remove the radiator cap to see if combustion gases are in the coolant.

Some dumb questions:

  • no chance that the exhaust hose has collapsed internally to create excessive back pressure?

  • no chance of a collapse or clog in the water lift muffler?

  • could cleaning/testing/replacing the anti-siphon valve on the hose from the heat exchanger help? Anti-siphon valves are installed for a reason …

Bil

Unfortunate that Marty Chin isn’t still part of the forum!

Bil Wrote:

Ouch! I hadn’t heard about this before, Scott.
Thanks for the heads up.

I’ll look forward to learning how you resolve
this.

A perception check: am I right in understanding
that, after you stop the engine, water is somehow
entering the exhaust manifold. And the prime
suspect is water from the exhaust, not coolant
penetrating from some internal fault in the
engine?

Exactly so.

If it were engine coolant that was leaking, then
your coolant expansion tank would be running low.
And your freshwater coolant would be being
pressurised with combustion gases. If it were a
car engine with a radiator, I’d remove the
radiator cap to see if combustion gases are in the
coolant.

No, only problem is this intermittent water lock, everything else about the engine is well maintained and checks out ok.And the engine normally starts right up and runs smoothly. We removed the injectors and got the water out, checked piston to head clearance, put it back together and it started right up and ran normally. .004 clearance is within specs so no con rod damage.

Some dumb questions:

  • no chance that the exhaust hose has collapsed
    internally to create excessive back pressure?

  • no chance of a collapse or clog in the water
    lift muffler?

  • could cleaning/testing/replacing the anti-siphon
    valve on the hose from the heat exchanger help?
    Anti-siphon valves are installed for a reason …

Prime suspect at the moment is either a blocked anti-syhon valve or not enough anti-syphon hose height above waterline and manifold. And an on-the- small-side water lift muffler. The design distances between waterline, engine, elbow, anti-syphon valve are less than idea. but Obviously more or less ok because this is a very occasional problem. Last time this happened we replaced the elbow and the anti syphon valve and declared the problem solved. Wrong.

Being an intermittent problem there’s really now sure way to be sure the problem is solved, no matter what we do! Good, experienced and attentive to the problem yard staff here in Oriental and we revisit the problem Monday. In the meantime I’m going over other systems and catching up on maintenance, especially a VHF antenna SWR error. Easily and expensivly fixed, I expect.

Bil

Scott: Hi!

Prime suspect at the moment is either a blocked
anti-syhon valve or not enough anti-syphon hose
height above waterline and manifold. And an
on-the- small-side water lift muffler. The design
distances between waterline, engine, elbow,
anti-syphon valve are less than idea. but
Obviously more or less ok because this is a very
occasional problem. Last time this happened we
replaced the elbow and the anti syphon valve and
declared the problem solved. Wrong.

I’ve in the past measured the head from the base of the waterlift muffler to the top of the curve of the exhaust hose (45 inches), but I’ve not measured and noted the height of the vented loop.

Z’s vented loop is a Scot Pump, part number 890-913-VB-18F, from www.scotpumpflorida.com. I last contacted them by email in 2014, when they quoted me $18.80 for a new vented loop (funny, when I now check my records I find I ordered a new one in 2014 and Scot Pump never actioned my order!).

I think that means I’m overdue to pull the vented loop, clean it and re-install it and perhaps think of buying about the only decent vented loop available in Australia, a Nanni Diesel syphon break that retails for about 5 times the Scot Pump one (must be good, no?!)

Z’s Scot Pump vented loop is mounted as high as possible in the engine room, on the forward face of bulkhead #7.

Z was built with a Salisbury Hydro-Silencer SBM-20 waterlift muffler. WH Salisbury Co used to be based in Skokie, Ill. But Honeywell bought the company and refocused it to manufacture industrial safety products. The Salisbury muffler has an internal volume of 2.5 litre (2.6 quarts/0.66 gallon). If I need to replace I’d be looking at a Nanni Diesel Waterlock muffler that has roughly double the internal capacity.

maintenance, especially a VHF antenna SWR error.
Easily and expensivly fixed, I expect.

For our first Zygote, I had a SWR meter and I used to check such things. With Z, I’ve not once had reason to think about it!

Last year when we pulled the mast, repainted it, replaced a length of conduit inside, etc, I replaced Z’s original masthead VHF antenna (and ran new cable, replacing 15 year old RG-8U with RG213 too).

But again I didn’t measure SWR. What symptoms have you suffered?

Bil

Bil Wrote:

Scott: Hi!

Bil,
Thanks for all the detail below vis a vis your anti-syphon setup.

When we get back to work on it Monday we may do some rerouting of the antisyphon loop, and relace the muffler with one having greater volume. But, having pondered the dates and circumstances of this last and the previous water lock, overnight I came up with a new theory. Over all the past years of sailing Itchen I ALWAYS closed the raw water intake when not running the engine, and especially so when leaving her unused for any length of time. Looking back, in both instances of wwater lock I had left the seacock open for quite a few hours, at least overnight. I think water is finding it’s way through the Johnson raw water pump ino the manifold and down into one or more cylinders.

Itchen’s Yanmar manifold is definitely slightly below the loaded water level.

Back to my previous practice from now on, shut the seacock whenever the engine is shut down, and make sure all crew are well-aware of the need to check and open the seacock before starting the engine! And, though I have never had this problem yet, consider shutting the seacock when bitter cold Maine weather leads to slow starting and extended engine cranking, to eliminate any possibility of pumping water into the manifold.

Prime suspect at the moment is either a
blocked
anti-syhon valve or not enough anti-syphon
hose
height above waterline and manifold. And an
on-the- small-side water lift muffler. The
design
distances between waterline, engine, elbow,
anti-syphon valve are less than idea. but
Obviously more or less ok because this is a
very
occasional problem. Last time this happened
we
replaced the elbow and the anti syphon valve
and
declared the problem solved. Wrong.

I’ve in the past measured the head from the base
of the waterlift muffler to the top of the curve
of the exhaust hose (45 inches), but I’ve not
measured and noted the height of the vented loop.

Z’s vented loop is a Scot Pump, part number
890-913-VB-18F, from www.scotpumpflorida.com. I
last contacted them by email in 2014, when they
quoted me $18.80 for a new vented loop (funny,
when I now check my records I find I ordered a new
one in 2014 and Scot Pump never actioned my
order!).

I think that means I’m overdue to pull the vented
loop, clean it and re-install it and perhaps think
of buying about the only decent vented loop
available in Australia, a Nanni Diesel syphon
break that retails for about 5 times the Scot Pump
one (must be good, no?!)

Z’s Scot Pump vented loop is mounted as high as
possible in the engine room, on the forward face
of bulkhead #7.

Z was built with a Salisbury Hydro-Silencer SBM-20
waterlift muffler. WH Salisbury Co used to be
based in Skokie, Ill. But Honeywell bought the
company and refocused it to manufacture industrial
safety products. The Salisbury muffler has an
internal volume of 2.5 litre (2.6 quarts/0.66
gallon). If I need to replace I’d be looking at a
Nanni Diesel Waterlock muffler that has roughly
double the internal capacity.

maintenance, especially a VHF antenna SWR
error.
Easily and expensivly fixed, I expect.

For our first Zygote, I had a SWR meter and I used
to check such things. With Z, I’ve not once had
reason to think about it!

Last year when we pulled the mast, repainted it,
replaced a length of conduit inside, etc, I
replaced Z’s original masthead VHF antenna (and
ran new cable, replacing 15 year old RG-8U with
RG213 too).

But again I didn’t measure SWR. What symptoms have
you suffered?

  1. SWR error messages every few minutes from the Vesper Watchmate 850 AIS transponder, echoed by the Raymarine C80, driving us crazy with insistent alarm beeps.
  2. Miserable output from the ICOM IC-M506. Had a very experienced electronics guy go over it all yesterday with professional meter and dummy load, and found:
    a) a short in the radio to mast heel run of cable, hidden during a recent water tank replacement installed when I was not around to advise on where to rerun the old cable.
    b) only 11+ volts power at the radio - which was putting out 17 watts instead of its rated 25W – so I willcheck connections and maybe up the size of the feed line.
    c) Marginal, not terrible but not great SWR and output readings for the mast cable and masthead antenna, even though the connections looked good.

So will sort out and fix all that come Monday.

Bil

BCC 116 Zygote,
Scarborough Marina, Moreton Bay, Queensland,
Australia