Join Date: Jan 2012
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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!