96 Johnson 112 SPL rectifier questions / problems

[StriperChaser]

The tachometer began working irratic and finally quit this weekend. The shop manual says that is a sign of possible charging problems generally associated with the rectifier. That rectifier was just replaced last fall by the dealer who has now gone out of business. Any ideas of what could make this happen repeatedly if that's the problem. Seems there's always something going wrong with this engine, was it just a dog or what?

 

[Trent]

Re: 96 Johnson 112 SPL rectifier questions / problems

Hooking up the battery backwards, stator charging winding shorting out, too much load on the system are just a few causes of failure.<br /><br />To check to see if its bad. Check battery voltage before cranking, (should be about 12.5 volts). Then check it after cranking and it should rise above 13volts. If so its working.

 

[Dhadley]

Re: 96 Johnson 112 SPL rectifier questions / problems

Also wing nuts seem to be a possible source of trouble also. You may want to consider venting the block (if not done already) since this is a "repeat" problem.<br /><br />Good luck!

 

[StriperChaser]

Re: 96 Johnson 112 SPL rectifier questions / problems

Dhadley mentioned venting the block. What exactly are you refering to? I ran the cranking battery completely down on Friday night using the lights and had to use a spare battery at daylight to get the motor started. I ran about 10 miles back to the ramp with that spare battery hooked up and may not have had both leads real secure. Could that have damaged the rectifier? I'm looking for the cause of the problem just to keep it from happening again.