Join Date: Aug 2007
Location: Fort Erie
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Universal 5411 cooling system
In my new to me old boat, cooling water goes from the thru hull to the pump, thru the engine to the manifold then out at the thermostat housing. From there a hose at the bottom of the thermostat housing and a hose at the top of the housing both go to either side of a "T" then into the exhaust line and muffler.
When I look at the drawing from the manual the hose at the bottom of the thermostat housing should go to a "T" which sits on top of the thru hull.
text from the manual below.
[I]1. Sea water enters through sea water inlet,
2. Through sea water valve when open,
3. Into mixing tee to suction side of pump, located below water line.
4. Out of pump by hose to inlet on side of block,
5. Circulates through block into cylinder head,
6. Leaves head on top front to exhaust manifold,
7. Circulates through manifold to thermostat,
8. Enters thermostat which remains closed during warm up, permitting a small amount of water to
enter exhaust system for cooling and overboard
9. As engine temperature rises the thermostat starts to open, letting hot water enter exhaust line. At
the same time the same amount of cool sea water is drawn in by the pump to replace the discharged
hot water. This is done through the mixing tee which is located below engine (or water line) to
prevent air from entering the system.
10. There may be some fluctuation in engine temperature until engine stabilizes.
11. In areas of cold inlet say 50oF, you may notice some movement from 136oF to 155oF as engine
r.p.m. are changed. This is less noticeable with warmer inlet waters. The reason being that the
colder water causes thermostat to react faster than engine temperature stabilizes.
Is there a problem the way mine is set up with the mixing T at the muffler, well above the water line rather than at the thru hull?
I was not getting any tepmerature reading on the gauge, when I started looking, the temperature sending unit was missing from the side of the thermostat housing, it had been replaced with a tapped plug.
I have purchased a sending unit which I plan on installing this weekend to see if I get a reading.
I was wondering at the same time should I change the location of the mixing T ?