no spark and rectifier question.

[newbie600rr]

I have a 82 50hp johnson that I had a little problem with. I have 2 questions.
1. Would a low battery cause a no spark situation. I have been doing some work on my boat and have not had the motor running for about a month. Went to go start it yesterday and had no spark. Did a few test and didnt come up with an answer to my problem. Tried today and same problem. Put the charger on for a few minutes and it started right up. Tried it about 4-5 times thruout the day and no problems. Would a dead battery cause this.

2. I think my rectifier is bad. I did the test and only had movement on the meter while touching the black to ground and red to the three yellow wires. No other movement on the meter so I think it is bad. My question is will it hurt anything if I run it with a bad rectifier. It is suppost to charge the battery but with the bad rectifier will the motor pull a drain on the battery while it is running causing a dead battery. I really want to use it this weekend but dont want to cause more harm.

Thanks

Chris

 

[Joe Reeves]

Re: no spark and rectifier question.

The engine must crank over at least 300 rpm in order for the stator to energize the powerpack (ignition)...... slow cranking engine = no ignition.

Running with a bad rectifier causes the stator to overheat.... not a good idea.

Is this the test you ran?

(Small Rectifier Test)
(J. Reeves)

Remove the rectifier wires from the terminal block. Using a ohm meter, connect the black lead of the ohm meter to the rectifier base (ground), then one by one, connect the red lead of the ohm meter to the yellow, yellow/gray, then the red wire (some rectifiers may also have a fourth yellow/blue wire. If so connect to that also). Now, reverse the ohm meter leads and check those same wires again. You should get a reading in one direction, and none at all in the other direction.

Now, connect the black lead of the ohm meter to the red wire. One by one, connect the red lead of the ohm meter to the yellow, yellow/gray, and if present, the yellow/blue wire. Then reverse the leads, checking the wires again. Once more, you should get a reading in one direction and none in the other.

Note that the reading obtained from the red rectifier wire will be lower then what is obtained from the other wires.

Any deviation from the "Reading", "No Reading" as above indicates a faulty rectifier. Note that a rectifier will not tolerate reverse polarity. Simply touching the battery with the cables in the reverse order or hooking up a battery charger backwards will blow the diodes in the rectifier assy immediately.

If it is, then you know if the rectifier is bad or not.

 

[newbie600rr]

Re: no spark and rectifier question.

That is the test i did. I got no reading while connecting a probe to the red wire and one to any other wire. Reversed it and still no reading so that is why I think it is bad.

 

[Joe Reeves]

Re: no spark and rectifier question.

Sounds that way. Replace it.