72 521 electrical problem

[EvilTwin182]

Help, I am completely stuck here is what I have yesterday started the truck to leave no problem but all of the sudden complete loss of power let up on the accelerator and truck resumes idle. It has duel points and from all the diagrams I can find none of them seem to match up with the color combos that are on the harness i have making it extremely difficult to figure out what is wrong my fear is that I have a faulty relay but have no idea in how to determine.

[datzenmike]

If it idles then it is unlikely electrical.

 

A plugged main jet would cause loss of power and yet leave the idle circuit working.

[ggzilla]

There is no relay involved in running the engine.

 

Im in seattle, could take a look at it. PM sent.

[EvilTwin182]

At this point I feel like Im going in circles and not making any progress I welcome any help

Please call

206-915-9033

[EvilTwin182]

Just some more info the reason I believe the issue is electrical when the problem first happened there was magic smoke coming out of the dizzy upon further inspection I found that one of the heat shields had melted

[DanielC]

There are some inaccurate electrical diagrams out there, but there are also some good ones.

On this page, part way down, you can download a PDF of the factory service manual.

http://www.davidcmur...dat/620tech.htm

 

In the 521 FSM, there is a 521 wiring diagram, but I believe it does not have the wires for the second set of points.

 

in the 521 section, there is a 521 wiring diagram, but it is for a J13 521, and won't be right. I have also cane across a lot of 620 wiring diagrams labelled as a 521 wiring diagram.

 

The retarded set of points, on a stock 521 only function in third gear, part throttle, with the clutch not depressed. I believe the wiring is set up so the retarded set of points is disconnected, until all the conditions are met, and they are just switched in parallel twith the advanced set of points. Unplugging the retarded set of points at the distributor takes them out of the circuit.

 

Having said all that, it still sounds more like a fuel problem to me. Make sure your main jets are clean, and there is no water in the carb.

[DanielC]

I just saw your reply about "magic smoke"

inside a points distributor you have wires, and two switches. And power to get to the distributor has to go through the coil, and the ballast resistor. In fact, the distributors job is to short the coil to ground, so when the points open again, the coil creates a spark.

 

There is nothing inside a points distributor that will create magic smoke, unless it is hooked up to a battery, without the coil and ballast resistor in series with it.

[banzai510(hainz)]

the main point wire will be the wire going to the big capcitor side. I think its a blk red wire. the other side will have the smaller capictor and you can pull the wire to not use the 2nd set of points. Most times its not even used untill the 3rd gear switch is used. But never really found where they were on a 521 myself.

 

I always just used the main set of points .

 

Use only a stock 521 coil and use the ballst resisitor.

 

GGzilla can hook you up, if close by

 

but best to find a EI ignition or a a used Pertronix conversion on the used market. I find that most people cant handle the complexity of points and how to maintain them. it will be the best 100$ ever spent.