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post #1 of 8 Old 02-05-2012 Thread Starter
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Troubleshooting a Raw Water Cooled Farymann

I have a Farymann R30 v-twin, raw water cooled diesel. Last year, I replaced all the hoses and believed I had the engine running well. When running, cylinder covers were warm to the touch and the manifold could be touched, but not for too long. The exhaust would spit what seems to be typical water/exhaust mix.

This motor has a jabsco pump which feeds a 3 way splitter - 1 to each of 2 cylinder water jackets, 1 to the manifold. The outlet of the water jackets have thermostats which then lead to the manifold as well.

There is one outlet from the manifold which goes to a Y above the waterline (I suppose this should be a anti-siphon, but isn't), of which 1 side returns back to the manifold and the other leads out the stern. The exhaust leads to a muffler/water baffle, then out the stern as well.

Recently, I found the outlet from the Y to stern to have a blockage. So, I cleared it... Now, when I run the motor, the outlet from the splitter has a steady stream - it only ever had a trickle - and there is very little water coming through the exhaust, some, but very little.

The cylinder covers are still warm to touch. Touching the thermostats are cold - even colder than room temperature - almost as if they were pushing raw sea water (I'm in the northwest - water temperatures are about 45-50) without being heated. The manifold does seem a bit hotter than before.

Occassionally (once or twice a year), I'll run some vinegar through the system, letting it sit for a day or two, which I did end of last year. I follow that with some fresh water which I let sit until I need to run the motor again. Recently, under the motor I found some gooky, very well, kind of greasy, kind of putty, like substance.

I wonder if my water jacket(s) is(are) clogged? Is it safe to remove the hose from the outlet of the water jacket (post thermostat) and let the engine run? I can either catch the outlet water or let it run to the bilge.

Is it normal to have a good steady stream out of the (not sure what it's called) Y outlet from the manifold and not have water (or much water) coming out of the exhaust mix?

Any good references on Farymann diesels and/or books about diesels that go indepth about cooling systems, particularly raw water cooled systems?

Thanks in advance for any assistance.
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post #2 of 8 Old 02-05-2012
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I've a friend with the same engine. Don't know if they can help you but there is a USA dealer Farymann Diesel :: North America

"Next best thing to not having a boat? The knowledge from having one!" Denise, Bristol PA, On Tidal Delaware River, Anchor Yacht Club.
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post #3 of 8 Old 02-06-2012
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Farymann and Universal Atomic exhaust manifolds are prone to 'slab rust'.

Cast iron castings, when they cool in their mold, form 'stratifications' - like an onion is 'stratified'. When rusting (ferric rust or 'red' rust') penetrates between these 'stratifications', the formation of low density rust develops high pressure and 'pushes' the stratifications apart, the now broken fragments fall to the bottom of the water passages .... available to occasionally block the channels especially the outlet nozzle. Turbulent flow within the manifold will sometimes 'move' these fragments .... some will pass out but sometimes will be large enough to partially or fully block flow. Usually the outlet on such Farymann or Universal manifolds at at the 'top' ... and when the engine with 'top outlet manifold' is shut down, the water flow stops and the particles fall back down ..... creating a 'mystery' of manifold blocking and engine overheating.

Most naval salt water raw cooled engines are never shut down because of this slab rust phenomenon ..... and the reason is that if the cast iron is kept 'hot' the rust formation will be a 'protective' black form of rust - ferrous rust. Upon non-operating shut down conditions this black ferrous rust will change to destructive red/ferric rust ... and will again have the propensity to 'push' the casting internals apart.

So if the engine/manifold is raw water cooled and to prevent slab rust formation:
1. run the engine 'hard' for long periods of time so that it 'heat soaks' and develops the protective black/ferrous protective rust.
2. Dont 'dry out' the engine when long term stored .... fill the engine and manifold with an antifreeze containing 'rust inhibiters'.
3. Consider to instal a heat exchanger, and fill the 'fresh water' side with antifreeze with rust inhibiters

The danger is that such manifolds will eventually develop pin-hole leaks between the water side and the exhaust gas side, and the cooling water will soon drain back and into a cylinder. Scale removal from such engines/manifolds should only done with an 'inhibited' boiler descaler such as RydLyme, etc. and NEVER with an 'acid'. Once descaled the engine should be run hard and under load to reform any 'rust' and 'bright surfaces' back to the 'ferrous'/black rust condition.
When these manifolds/engines become 'old', they should be periodically 'pressure tested' to validate that they dont have 'communicating' pin-holes.

hope this helps.
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post #4 of 8 Old 02-06-2012
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Could you post a picture of the arrangement?
I could not quite understand the plumbing.
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post #5 of 8 Old 02-08-2012
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There is a very nice individual by the name of Dave, with Entec West Inc 971-255-1561. Contact him for parts or advice on Farymann. Do not waste your time with Farymann North America. I've dealt with them for many occasions before finding Dave and there is no comparison in knowledge and professionalism, even with parts availability.

I'm dealing with a similar issue, only that my Genset engine is a one cylinder Farymann 18w435 (small engine raw water cooled). After overhauling it I ran it and water is getting to the top of the piston. A real mystery. My thread is Water in the cylinder. After checking everything everybody has adviced and thought of, I'm at the point of pressure testing the exhaust manifold for pin-hole leaks. Like RichH is mentioning.

Good luck and don't waste your time with Farymann North America.
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post #6 of 8 Old 02-11-2012
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Both my main engine and gen set drain exhaust muffler into bilge when turned off .No surprises.and easy to rig.
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post #7 of 8 Old 02-19-2012
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I have a Farymann A30M which is ("knock of wood") running fine at the moment. My concern is not knowing what condition the water jacket is and having an unexpected failure whilst out cruising. I'm curious about the "pressure testing" mentioned an what is involved. Is this something a DIY'er can easily do or does it require some special equipment/expertise?
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post #8 of 8 Old 02-20-2012 Thread Starter
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Figured out the problem(s), and things are back to normal - explanation below. But first, thanks for all your responses...

Denise, thank you for the Farymann contact!

RichH, Excellent info! Especially about the RydLyme.. no more Vinegar for me.. but I do intend to put a selector valve on the intake so I can flush with fresh water easily after every use.

Rockter, no pics, but thanks for offering to help.

Mikey, I've spoken with Dave at Entec many times - you're right, Great Guy. In fact, he has (in the past) convinced me that my motor is worth trying to keep. If I can keep it in good shape, should last a long time.

Capt Len, Denis, also thanks!

Here's what I figured out... The book Know Your Boat's Diesel Engine, by Andrew Simpson - ISBN: 978-0-07-149343-7 has good descriptions and diagrams. I also snuk a look at Calder's book while at West Marine - it's ok, but not enough raw cooling info.

Turns out that if a motor is mounted below the waterline, they run a hose out of the manifold up to an anti-siphon or vented loop, then back down to the manifold. The old arrangement, using bronze fittings, had hose from manifold, back to manifold and the top part was a vent hose to the transom. It clogged and so the system really sort of worked... there was a trickle when the engine ran and there was pressur. When the engine stopped, and negative pressure exists, air would flow from the transome and break the potential siphon. When I took it apart and cleaned it... I broke the limiting clog in the system.

Today I replaced the bronze with a Forespar Vented Loop which works like a charm! That also frees up a transom hose for an extra bilge pump which I will be installing later this year.

As already mentioned, very soon, I'll put a 'Y' selector on the intake to select either raw salt or fresh water so that after every run, before shutting down, I can flush the motor of salt water.

But I really like RichH suggestion of adding a heat exchange. If/when I test the system with pressure and it passes the test, I'll seriously consider that.

Dennis, regarding if the test can be done DIY - testing the vented loop was pretty simple. I would expect that (although a bit of work) if you take each hose from the manifold, detatch it from it's opposite end, seal each one off with a bolt and hose clamp, you should be able to seal it from leaks. Then, unseal 2 hoses - blow carefully and lightly into the hose you want to test and feel if pressure persists. If it's a very small pin leak, you might need a pressure gauge and bicycle pump set up. But I stress - be careful and use only the lightest of pressures - if there is a marginal area that's working ok, and may work for years, you could cause it to become a leak unnecessarily. Some say that's a good thing but with the availability of Farymann parts - I'd be very careful to baby them.

Thanks again All!
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