Thermostat

[mgram]

Hello all. I'm a new-ish owner of a '76 Tartan 30 that I bought two springs ago. This forum has been invaluable to me as I navigate this great old engine. One of the POs had seemed to install a garden spigot on the top of the thermostat housing. My instructions are to give a half turn before start up and then close it when I shut the engine off. I have seen many pics of the A4 thermostats and never saw this feature. Has anyone seen this, and does anyone know why this alteration was needed?

Thanks everyone.

[Sam]

I think a picture would help with responses showing the plumbing in and out and where connected.

[Dave Neptune]

Perhaps it is being used as a bypass valve. A picture would clear up a lot of questions. I have seen garden valves installed in the cooling system many times however they were used for flushing after use.

Is the valve hooked to anything or just on top of the housing? Very confusing information posted here.

Dave Neptune

[ndutton]

While we are waiting on pictures, in general adding a hose bibb suggests connecting a hose to it at some time for a purpose, usually a fresh water flush. However, I can't imagine a worse place for such an attachment if for no other reason than it damages the bypass port on the underside of the thermostat housing, a critical part of the dual action thermostat system.

[mgram]

Sorry for the confusion. I misstated the situation. The bibb in NOT on the housing like I thought. The engine fumes must be getting to me. It is on the raw water hose leading to the Thermostat. I was instructed to give it a half a turn before starting the engine and then closing it again after turning it off. I'll be at the boat tomorrow solving a new problem, I think water got into the tank after the torrential rains of last week on the east coast. I'll post pictures.

[mgram]

the handle is top right above the alternator

[Dave Neptune]

That valve is what we consider the "bypass valve" to control engine temps when running without a thermostat. Opening the valve increases the water "bypassing" the engine block which is fed by the "tee" fitting on the side plate under the alternator.

The bypass valve is a very common modification to the A-4. However there is no reason to close it after operating. I ran that setup for 34 years and only "adjusted" it if the engine was running to cold in the winter chilled waters or to warm in the summer water, or when a water pump was beginning to fail. It is easy to set and should be done at your "high" cruising speed. The temp is slow to react so adjusting takes some time. Only adjust about a 1/2 turn at a time or when using a ball valve moving the lever in small increments. After adjusting check the temp after about 5 minutes or a bit longer. In salt water set no higher than 130 degrees as once shut down the temp of the internals will add some temp. Salts will deposit and fowl things up at anything over 160.

Opening the valve raises the temp and closing the valve cools the temp, quite simple.

Why are your cooling hoses wrapped?

Dave Neptune

[joe_db]

What the heck is that wrapping?
Also is there an infamous trailer plug under that wrapping

[mgram]

The picture is from last Winter when I stripped, primed and painted the engine.

[sastanley]

Ha...as you can see, we are all about the details, mgram. Welcome. I have pics like that too. (well, i removed the hoses and replaced with new and used old spark plugs), but it's all good.

[mgram]

What the heck is that wrapping?
Also is there an infamous trailer plug under that wrapping

I don't know what that is, but is that something that's going to help my boat explode?

[mgram]

Ha...as you can see, we are all about the details, mgram. Welcome. I have pics like that too. (well, i removed the hoses and replaced with new and used old spark plugs), but it's all good.

Thank you for the welcome. How often should you replace hoses?

[Dave Neptune]

Replace when you see any kind of cracks, they will usually appear on the cut ends. I bit the bullet and replaced mine from the through hull to the water injection on the exhaust with Goodyear silicone hose. It is rated to higher temps and last at least 3 times as long. It is easier to work with too, well worth the piece of mind and the additional expense IMHO.

Dave Neptune