Re: [caborico] overheating on Universal M-50

[Thierry Danz]

Questions:  Does the overheating alarm go off?  For a fresh water cooled engine 180 deg F is normal operating temperature.  If it usually runs at 165F at cruising rpm, I would suspect a thermostat stuck in the open position.  Is 2500 rpm the engine's specified max rpm?  Do you reach this rpm under load?  If not, you may have too much pitch, or too big  a prop.  Could also be a foul prop and bottom.  In these two scenarios you would also see dark smoke from the exhaust at max rpm. I would get an infra red heat sensor.  I bought a small one at Sears years ago.  Not expensive, and a very handy gadget to have on board.

Thierry

CR 42#12 CURLEW

Baltimore, MD

-----Original Message----- 

From: Capn_Earl
Sent: Nov 17, 2012 7:18 AM
To: cabo...@googlegroups.com
Subject: [caborico] overheating on Universal M-50

I'm looking for advice about a stubborn overheating problem on my 1996 Universal M-50.  Engine runs at about 165 degrees until I push it into it's 2,000-2500 RPM range, then it overheats starting at 180 degrees.  (It will sit at dock in neutral and run 2000-2500 without a problem, it is just when it is under load that it overheats.)

I've addressed the usual suspects:  impeller, thermostat, tightened belt, cleaned the heat exchanger, coolant is topped off, verified water flow from the seacock through to the exhaust elbow, inspected elbow (there was corrosion built up and had to dislodge it).  I have not replaced the sensor but thought it was at least reading different temp levels and reporting them, but...  My next step is getting someone with a heat gun to shoot some temps.

Any other ideas?

Capn_Earl
Voyager CR38

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Thierry

[Capn_Earl]

Yes, the overheating alarm does go off when it reaches 180.  Have seen that before with a clogged filter strainer too.  2500 is indeed the max rpm of this engine.  I'm getting overheating at all rpm's above 2000.  When Isaac came by here recently, I hauled the boat out.  I installed new zinc at the propeller and cleaned the prop (wasn't very dirty).  Bottom has been cleaned and was all visibly good when out of the water.  Hadn't seen this problem before the boat was hauled, however.  I installed a new thermostat as part of the troubleshooting.

Sounds like heat sensor is the next step.  Thank Thierry

Capn_Earl
Voyager CR38
Currently Orange Beach, Al.

[Cab...@aol.com]

Heat exchangers don't last more than 10 to 15 years, then no matter how well you clean them, they will not transfer the heat. Next make sure you are not necking down your flow by running it right through a water heater with no by-pass.

 

Breck Caine CR 38 #19

[Capn_Earl]

Well, I wanted to finalize this post of mine.  The culprit was the alternator regulator as well as the battery isolator.  The alternator / regulator were not getting the feedback via the isolator so the alternator was sending 18 V to the starting battery - the isolator's two branches to the 2 battery banks were dead.  The first battery bank had the sensor that loops back to the regulator via the isolator to tell it to chill out but it was never getting any message to throttle back the volts.  The 3 different instruments that were out of wack - temp, oil pressure and CO monitor didn't like the excessive voltage in their systems.  All is well now after installing the Balmar Max Charger MC-614 regulator and ProMariner isolator (with much help from a tech).  Looking forward to good sailing weather coming up here in the Orange Beach, Al. / Pensacola, Fl. area.

Capn_Eearl
Voyager, Hull #177

On Saturday, November 17, 2012 8:20:35 AM UTC-5, Thierry wrote: