TAMD 41, need to install H20 Temp gauge

Anybody add a mechanical water temp gauge on a TAMD 41. I can not use the electric temp gauge port due to it being a different thread. I purchased two Murphy gauges to install and need to locate a non used plug for fresh water side. I want to have a alarmed adjustable water temp gauge. The electric sender did not go off when I was at 210 deg and climbing. I changed coolant and oil and the engines seem to run a cooler. I can run about 3200 rpms and temp stays around 195 deg. I think the thermostats are wide open at 195 deg. Thanks for any input. I previously posted this question under Engines, plumbing, electronics but did not get any info/response. I just pulled my port Alternator, Tach pegged to 5000 rpms when engine is running. When both engines are running, I was showing about 13.5 volts. I assumed that both engines were charging. Let port engine run by itself and only showed 12.5 volts on house batteries, pulled Alternator and took to Broadway Auto Electric, rectifier burnt out. Complete rebuild $185. I guess water may have dripped on the alternator, maybe after a wash down or from the heat exchanger that sits directly above the Alternator. . Bought the boat with this problem. But just another way to get to know my boat. Excellent sea boat. And very dry inside the cabin. Love the Outerbanks. Al

Al

When I bought my boat, I didn't trust any of the gauges or alarms until I tested them. I pulled the water temp sensor and alarm switch, then heated them up in a pan of water to verify the gauge tracked a test thermometer and see where the alarm would sound. I also found my alarm horn was bad.

I think I have the wiring diagram for the 41 if you need a copy for your file.

Mike

Mike, I bought the workshop manual from QMS for $20 It has the schematic for 12 or 24 volt. thanks for the offer. I ended up pulling my Port altenator. I was being fooled by the Stbd engine back feeding voltage into the port volt gauge showing 13.5 volts, it was actually the Stbd engine alternator charging the batteries. What made me start looking at the charging ciruit was that my port Tach was pegged at 5000 rpms. I found that the volts were only 12 on the port engine after I tried only running one engine at a time. $180 later I will install the alternator tomorrow at dawn and then ck the tach. The W or grey wire from the alternator should be 7 dc volts. My Stbfd alt. is at 7 but after cking at the alt form the port engine, I had 9 volts. The alternator was very corroded. I think water came in under the hatch cover and smoked the port alternator. I need to also ck if the heat exchanger is dripping onto the alt. If you or anyone else goes through alternaters, let me know, maybe we can figure out a type shiled that can be installed.
Al

Al,

A shield should be pretty easy to make for the alternator. I'd locate a cheap plastic container that is a little larger than the alternator and start trimming until it will slide over the top of the alternator. You might need to cut a slot for wires. I would keep an airspace between the alt and shield and use long wire ties to hold it in place.

Good luck and let us know how it turns out.

Bill

I'd be careful trying to put a shield around the alternator. Ever notice all those fan looking blades right behind the pulley? They are drawing lots of air through the alternator, keeping it cool. The brushes, diodes and bearings all need some cooling.

Side note: I read that GM now has a water-cooled alternator design.

The shield is rubber with a tie wrap around it I will keep a eye on it. I will remove after I run the boat for a few trips. I want to see if any deck water or hoses may be getting the Alternator wet. That back part is open. The air is drawn from the wire side and goes out the front. The way it is will help deflect the engine heat and pick up more bilge air, wich is actualy cooler. I already thought of what you mentioned. Of course Murphys law. I found that the rectifier went out in the alternator, probably due to the quick change in temp when water hit it. Went through the electrical wires around the batteries and dash to leasrn more about the boat wiring. At first I thought I had back feed to the Stbd alternator and burnt it oout, after installing the port alternator. Slowed down and started writing voltages down. Short part is that both alternatros are charging. When both engines are running, they feed into each battery banks via the battery switch for the engines. I tweeked the Tach, 1/4 turn counter clockwise. and the reading came down from 5000 to 700 rpms. I do not think it will stay because as I inserted the screw driver into the slot hole the needle swung full 0 then to 5000. I think there may be something loose inside. I will need to send the tach gauge somewhere to get checked out. Maybe Speedo-tach can do it or send to Volvo. Al

Bill, That is what I did. Back of Alt, plenty of air coming in the back and flow to front, Rick at Broadway auto electric said the air flow travels from back to front. Should also act as a heat shield from heat off of the engine block, will pull air from the bilge area. I used 3 large tie straps. Will ck if they get brittle at a later date. Not sure if I mentioned on another post that I got the port tach to work after I tweeked the scew adjustment on the back 1/4 turn CCW. It calls for 7 volts dc on the W (grey wire) lead to the tasch.. The rpm settled out at 700 rpm at idle. If it stays working for 10 or 20 hours I will then calibrate with a another tach of the engine. Al

Tachometer is showing 5000 rpm but does come back to 700 rpm after engine runs for a few minutes. Not sure what is going on but I suppose if it continues to be unpredictable I will have to purchase another tach for $180. Mounted the new mechanical gauges . Tapped into the thermostat housing. So far works good. Mechanical is about 5 deg below the elctric. Will get better reading when running at high rpms. Still in the driveway. Will be going out on Thursday for sea trials. Hope all goes well. Fishing is still up and down, including the weather. Al

I have a spare tach if you want to borrow it and make sure that is the issue before you buy one.

Thanks for the offer. I will keep that offer if I need to follow up. Thanks again, Al