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AQ125B Electrical Problem

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Dennis1950

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I replaced the points/condenser with Pertronix unit. Ran the engine in a barrel of water for more than an hour. Started with a just a touch of the key. Idled perfectly. Like a new engine! Took it to the lake (more than 100 mile round trip), started the engine, it ran for about 10 minutes and died. Took more than an hour to get it to restart. When it did restart, it ran rough, and only for about 15 minutes. Had to paddle back to the marina. Changed the coil, started double checking for bad wiring and found a resistor attached to the alternator. The wire goes to the coil. With the resistor in the line, I had no continuity from the coil to the alternator, no spark. Removed the resistor and now the engine again starts with just a touch of the key. Problem is the switch won't kill the engine! Had to starve the engine of fuel to shut it down! My question: Does anyone know what the resistor is? Is it the ballast resistor (which i don't need)? It is Volvo part # 834784. Any help is greatly appreciated.
 
I remember reading something similar on here not that long ago. I think the component is a diode that prevents feedback. Do a search on diode here and the thread will probably show up. I'm sure one of the other guys will chime in as well.
 
I did find the thread you refer to. Thanks. Is there a way to test this diode to see if it is good or needs replaced? And since this is not the ballast resistor, where is it hidden? I need to make it go away since my coil has internal resistance. Thanks again for your help.
 
Dennis,

I was thinking of ridding my points and converting to a Pertronix type unit, i guess you would recommend it? maybe upgrade to their coil? did you use ignitor? starts with ease?How long did it take and was it hard to install?
 
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If the internal resistance coil was already on the engine, you would not have a resistor or resistance wire. If you changed the coil and can't find a resistor, then the positive wire to the coil should be a resistive wire.

You can test the diode by doing a continuity check with a meter. You will have continuity in one direction, reverse the leads and you should not have continuity in the opposite direction. If there's continuity both ways, it's shorted. Idealy, disconnect one end of the circuit (maybe at the alternator).
 
The resistor is there as your coil if original works on 8v not 12v, there is also in the system a diode which is used to stop back emf to the coil, when this fails your engine will still run even thou the key is turned off. or will not charge to your battery.

Upgrade as i did to Pertronix but you will have to change the coil to a 12v coil and the buy the electronic spark module for your distributar, the resistor for the coil side will have to be removed completly or else the new spark module want work. keep the diode in the charging circuit if faulty just replace it with the same value marked on the side.

mark
 
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