I have a Johnson 150 HP 1983, I started the engine and then disconnected the battery leads from the starting battery. I tested for voltage at the cable ends. no voltage output. The engine remained running during this test. does this narrow down the defective components to one?
To answer your question yes.
replace the rectifier. CM
I agree but, for those of you reading this post........Do Not test Your Charging System this Way.......
Oh no! That is the worst way to check the system for sure!!! These aren't your Dad's Oldsmobiles!!! You definatly do not check the systems this way.
Well if you did not have charging system issues you might now.
I did not short out the cable every thing was isolated. I don't understand, does it have something to do with the ground?
You need to have the cables connected to a fully charged battery. That is the only way you can check a "load" on your motor.
What should your meter reeding at the battery posts if every thing is working ok?
12.58-13.2 VDC. If the rectifier is going whacked it will either over charge or under charge, usually they go high 14+.
So if it is bad it would only read what the voltage of the battery and there would be little or no amperage? if the rectifier was not doing its job would i read ac voltage?
Nope the only place AC is read is at the stator, the stator generates picks up the voltage for the motor from the flywheel magnets. Then it goes to the timer base, to provide the firing of the plugs. This is a general desription of the OMC ignition system and I have left out the PP. I don't have a '85 manual handy, on the later model of X-flows the rectifier is H20 cooled. CM
The output voltage should be 13.5....at the battery with a fully functional charging system.
Ok, Reconnected battery to motor and re tested the correct way. meter reading is 12.5 volts just above idle. removed rectifier and tested leads to ground. yellow and yellow/white both to ground and red .600 ohm to ground. bad rectifer?
Got a specific gravity battery tester? Test the cells on that battery. At idle you shouldn't be putting out much more than 12.5 V you need to run the motor up and check it under load but do it in the H20. Like Rusty says 13.5 V coming out. If not replace the rectifier. CM
It's a maintenance free battery less than a year old. The battery tested 13.7 v before starting. Do you think it is the battery? Should the yellow and yellow/white read to ground?
Didn't know what type of battery you had but if it reads 13.7 before cranking and then 12.5 when running then good chance the rectifier is shot.
The battery is under a replacement warranty for the first year, it may be a good idea to replace it also while it is still under warranty. Should any of the wires read to ground?
Rusty, What does a voltage rectifyer cost for a 1983 Johnson 150? Looks like i need one
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