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dbruce85 09-27-2012 08:05 PM

Universal 5411 Cooling
In my 1984 sailboat the 5411 is most likely original. It starts and runs good, a slight puff of white smoke when starting then no visible exhaust.
Did some trouble shooting on why my temp. gage never moves. I have crosses Lake Ontario under power for 5 hours with no movement on the gage.
I took out the gage and sensor, set it up on a table with two 6 volt batteries in series. Put the sensor in a cup of hot water and the gage registered the same temp( within 5 degrees) of an alcohol thermometer.
Next I reinstalled everything except the sensor, which I hooked up to the sensor wire, grounded the body to the block and did the hot water thing again. The gage again worked fine.
In the Universal manual it shows cooling water from the intake at the thruhull to the water pump, thru the block to an outlet at the bottom of the thermostat housing. The hose at the bottom is then supposed to connect to a "T" at the top of the water intake back at the thru hull. The hose at the top of the housing is attached to the exhaust. There is a small hole in the thermostat so some water would cool the exhaust while the thermostat is still closed. By the way I also tested the thermostat, it does open at about 140F.
In my hook up the hose from the bottom of the thermostat housing is Tee'd into the exhaust hose along with one one from the top of the housing.
I believe that means it is like running the engine with no thermostat at all.
At idle there is a good pulse of water out the exhaust about every two seconds. At 2000 rpm it is almost a steady stream of water out the exhaust.
The boat has always been a fresh water boat so with that flow of water it seems like there are no blockages in the engine.
My next step was going to be connecting the hose from the bottom of the housing to the "T" on the top of the thru hull, the way it shows in the manual. It currently has a plug on one side of the "T". Running the engine under load for a while and see if I get a reading on the gauge. Right now the engine is running always cold.
Has anyone seen this hook up before on a 5411, or is there any reason why I shouldn't proceed.

Rockter 09-28-2012 07:26 AM

Re: Universal 5411 Cooling
Did the temperature guage show a reading when the water temp was 140 F?

dbruce85 09-28-2012 08:19 AM

Re: Universal 5411 Cooling
I tested the thermostat outside the engine, in a cup of hot water at different temperatures, to see when it opens and closes. It was working fine

Bateau25 09-28-2012 09:40 AM

Re: Universal 5411 Cooling
My 5411 raw water cooling system is exactly as described in the manual, and I get a temperature range from around 100 to 136 degrees F. I get the same amount of water through the exhaust port as you described in your case. A few years ago, the 5411 was always running too cold (around 100 deg F max) so I reduced the 5/8 inch line from the bottom of the thermostat housing to around 3/8 inch using a home-made brass insert. That resulted in up to 136 deg F, which I believe is much better for the engine. just my 2 cents.

dbruce85 09-28-2012 09:52 AM

Re: Universal 5411 Cooling
How much difference do you see in the amount of exhaust water from when the thermostat is closed to when it opens?

Rockter 09-28-2012 10:20 AM

Re: Universal 5411 Cooling
Take both the thermostat and the temperature sensor out and put them in the same hot water bath on the boat.
Wire up a wee long earth return to the ship's battery earth from the temperature sensor otherwise it won't give a reading. Make sure ignition circuits are on but do not start the motor.
Put a wee bit of wood in the bottom of the hot water bath so that they don't rest on the bottom of the heating container. They may get far too hot if you do that.
Now heat the water up slowly and note the thermostat behaviour and the output to the temp guage.
I suspect that the guage is still reading zero when the thermostat opens???
Give it a try.

Bateau25 09-28-2012 10:32 AM

Re: Universal 5411 Cooling
Water starts to pulse out at around a cup's worth every second or two right after starting. When the temperature has climbed to about 135 deg F the amount of water pulsing out nearly doubles. At that temperature and under load with rpm around 2000 - 2300, water pulses out almost constantly and stays that way under load. At idle, it goes back to a pulse every one or two seconds plus a full discharge every now and then. So you see I spend a great deal of time observing my exhaust pipe! BTW, the temperature of the water pump also rises to around 118 deg F when the gage shows engine temp at 136 deg F. That is due to the mixing of hot returned water and cold raw water at the mixing tee. Hope this helps!

JimsCAL 09-28-2012 08:22 PM

Re: Universal 5411 Cooling
Sounds like a previous owner has modified the cooling system to eliminate the recirculation. I would go back to the arrangement in the Universal manual and see what happens.

dbruce85 10-02-2012 10:38 AM

Re: Universal 5411 Cooling
Switched hoses back to like the diagram in the manual. At start up and until the thermostat opened there is a lot less water out the exhaust ( only the water that is getting thru the small hole in the thermostat) when the thermostat opens the water increases.
Engine only runs at about 100F. Took it for a 1/2 hour run yesterday. When I brought the throttle back to idle position it went up to around 125F. Gave it a little throttle and within 4 or 5 seconds it was back to 100F ( with a lot of water out the exhaust).
I think the thermostat is opening too soon, a new one may be my next test.

JimsCAL 10-03-2012 08:01 AM

Re: Universal 5411 Cooling
The operation you describe initially is how it should operate - a little water out the exhaust until the thermostat begins to open, then increased flow. However, the flow should go up and down with the power as the need for cooling changes. Sounds like its not closing down again after you reduce power.

A new thermostat is worth a try. You're going to be shocked at what they cost however, but its worth having a spare onboard.

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