Rectifier issue

Loyd Dinneen

Active Member
Jul 29, 2017
484
Las Vegas
Boat Info
1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
Engines
Twin 470 Mercruisers
I have a 1977 sda 240 Sundancer srv Searay with twin 470's and I have just been working on a overheating issue on the stbd engine so I cleaned the riser and cleared all the passages. I then reinstalled everything topped off the coolant. I also installed two new batteries and hooked everything back up again. I then started it up and after it was running at 1500 rpms for about 10 or 15 minutes I smelled smoke and saw smoke coming from the front damper pully and could see a glow coming from the rectifier so I shut it down. Up until that time the system had been over charging with the old batteries but with the new ones was charging fine at 13.5 volts then started smoking. The port engine is doing just fine and charging at 12.5 volts as the battery is fully charged. Question I have is if the selector switch is on both can this effect anything as for the charging, seems to charge both batteries when one engine is running no matter which one. Honestly haven't quite figured out where to put the switch when running the motors. I feel the rectifier is shot on the stdbd engine so can I just disconnect the two wires from the rectifier and do the conversion really don't have much room to get at the damper to remove it.
 
Stator is still in the damper and no magnets have come loose just the coils got hot or the wire inside. Figured I would disconnect the wires from the rectifier at the regulator and install a conversion kit and leave the rectifier in place, really a very hard place to get into to remove the damper to take out the rectifier. Going out in a little bit to disconnect wires and restart engine to see if it still shorts out, I know it won't be charging.
 
The trouble with that system is it does not like weak/dead/ multiple batteries to try and charge. The stator puts out AC voltage from the magnets passing over the coils . If the yellow output leads or the coll wiring is shorted you will start a fire.
Post a pic of the front of the motor .
 
The stator didn't start on fire I didn't let it get that far. As soon as I saw smoke I shut the engine down and looked for the source and saw smoke coming out of the holes in the damper. I then restarted the engine and saw a red glow inside the damper and smoke so I shut down again since I now know where the smoke came from and figured the stator is fried, I have since disconnected the stator wires from the regulator and am looking into conversion kits.
I think what killed it was the coolant that dripped down onto the regulator and most likely shorted it out,a screwup on my part as I was testing the coolant temperture and it overflowed and dripped down on the regulator, up until that point everything was charging fine 13,5 volts 50 amps at 1500 rpm. I just created more work and expense for myself, getting tired of solving problems on this hole in the water. Just got thru repairing an exhaust riser to try to solve a running hot issue and buying and installing two new batteries as the others both died and were 5 years old. Will see about posting a picture when I can get my son to help me as I am tech stupid when it comes to that.
 
Here are some pics of the stbd engine. You can see how tight it is in there.
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