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Author Topic:   Damage to Rectifier From Jump Starting
Lyle g posted 03-24-2006 09:48 PM ET (US)   Profile for Lyle g   Send Email to Lyle g  
I believe [a component on my 1983 Evinrude 85-HP motor with the nomenclature Varo R315] is used to charge the batteries. What is the correct name of this item? Could I have burned it out by using a battery charger to start the motor?
jimh posted 03-24-2006 11:20 PM ET (US)     Profile for jimh  Send Email to jimh     
Use this GOOGLE.COM link to find information about an outboard motor component with the nomenclature Varo R315 ie=UTF-8&oe=UTF-8

It sounds like a rectifier.

Tom W Clark posted 03-24-2006 11:41 PM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     
Evinrude didn't make an 85 HP outboard motor in 1983. They stopped making an 85 HP motor in 1980. Are you sure you don't have an Evinrude 90?
Tom W Clark posted 03-25-2006 12:17 AM ET (US)     Profile for Tom W Clark  Send Email to Tom W Clark     

To buy a rectifier (or whatever part it is you may need) you will need to know exactly what and model and year motor you have.

Like the hull, the motor has an identification number on it, usually model number and serial number. A small placard should be riveted to the mounting bracket side. There may be a decal in lieu of this placard.

Tell us what number(s) are there and we can tell you what model and year your motor is. The number we are looking for will be something like: E85STLCSA

My suspicion is that your motor is older than your boat.

jimh posted 03-25-2006 09:44 AM ET (US)     Profile for jimh  Send Email to jimh     
Can a rectifier be damaged by the process of using a battery charger to start a motor?

When using a battery charger or any external source to provide the current needed to start a motor, there is always the potential for some sparking. Sparking indicates that the flow of current has been interrupted and then restarted. In any circuit in which the load has inductance, there is a great potential for damage to occur from sparking.

An inductive load, such as an electric motor, generates a magnetic field. When the flow of current is interrupted suddenly, the magnetic field collapses. The energy in the magnetic field induces a voltage in the windings of the motor. It is very possible that when this occurs a voltage spike will be generated. The voltage in the spike can be greater than the exciting voltage (the 12-volt battery) which operates the circuit.

If you attempt to start an engine with an external source temporarily connected, such as with clamp on connections, and during this process there is sparking at the connections, it is possible that harmful voltage transients could be generated. If the level of these transients exceeds the maximum reverse voltage junction rating of any rectifiers in the circuit, those rectifiers will be damaged.

Because of the potential for causing damage to other components of the battery charging system from sparking, I try to avoid charging a battery while it is still connected to the motor. And I certainly would avoid trying to start the motor from an external source like a battery charger, as this is almost guaranteed to generate some sparking. In an emergency situation, of course, I would try starting the motor this way, but for routine service, I recommend disconnecting the battery from the motor and then charging it. On most boats with a master battery switch, you can simply set the switch to OFF to disconnect the battery from the rest of the charging system.

jimh posted 03-25-2006 09:46 AM ET (US)     Profile for jimh  Send Email to jimh     
[Move to the SMALL BOAT ELECTRICAL discussion.]
Lyle g posted 03-25-2006 08:06 PM ET (US)     Profile for Lyle g  Send Email to Lyle g     
Thanks everyone. I purchased a replacement part for $15 from a local source. If tomorrow is a little warmer I will go for another trail run. Then next week I'am going to re-do the console, after I read Tom Clark's suggestions.

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