Fuses popping

[Raystar57]

Disconnect the + wire on the F2 terminals on the motor next. #4 in diagram.
You may have a shorted field to the case on the starer.
If no pop then remove the F1 wire also and measure resistance between
F1 or F2 to the starter case. Should have no connection.
If you do have a short the starter is bad.

Magneto short is possible but it is not powered when the key is off or when the switch is unplugged.

The ignition coil is connected to chassis ground and there would be two other ground to chassis connections that I see on the schematic.
One near the ground fuse and one near the magneto somewhere.
Blue in the diagram. These indicate a chassis connection.

[Lukedlv]

Thanks Ray. I disconnected f2 and f1 and checked resistance to the starter case with each post. When both were disconnected, there was no resistance when one multimeter prove touched the metal casing of the starter. Does that mean the starter is still good?

This is driving me crazy. I know there is some short because I can't even connect the battery, but I can't find it. The magneto is the piece that has two posts with resistance but the other two posts do not have resistance. I'm wondering if something worn out on it? Would that cause a fuse to blow with the key off?

Any other ideas of what I can check?

[Raystar57]

The field is not shorted to the starter case so that is good.
Starter may be good.

Go back to the diagram and unplug items 1,2,3 and 4 and leave them disconnected.
Tape up the cable #4 so it does not short to anything.
This removes all power to all possible components.

Connect the battery cable back up.
Does is pop?
If so then there is a wire in the harness that is making contact to ground somewhere.
It could be wore through the insulation around a bend.

If all is good then reconnect one item at a time and check.
Start with the #4 to the motor F2.
Then #3 to the relay.
Then #2 to the stop switch.
Then #1 to the key switch.

The magneto is not powered as it is an inductive input to the CDI module.
It generates a voltage which the CDI module amplifies to create a high voltage spark at the correct time.
If it were shorted the engine would not fire.

There is an error on the schematic on a wire color on the key switch but it is not part of your problem.
Orange box.

[Raystar57]

Found another error on the key switch logic connection diagram.
The bar between the R and B should be a N/C.
Maybe this has been fixed on an updated schematic.

[Lukedlv]

Ok, I followed your guidance. The fuse did not pop when I hooked up the negative cable while #4 was disconnected. Once I connected positive terminal to the #4 post on the starter, it popped. Does that mean the starter is bad? I changed the brushes last month, so maybe I did something when reinstalling? How can I determine if the starter itself is bad?

[Raystar57]

Remove A1 and A2 from the starter.
Ohm from A1 to case and A2 to case.
Should be no connection.
If beep or low ohm short connection, starter armature is shorted to the case. Fuse pop.

Recheck those brushes an insure no brush wire is causing the problem.

[Lukedlv]

Originally Posted by Raystar57

Remove A1 and A2 from the starter.
Ohm from A1 to case and A2 to case.
Should be no connection.
If beep or low ohm short connection, starter armature is shorted to the case. Fuse pop.

Recheck those brushes an insure no brush wire is causing the problem.

You are the man! I took the starter out and taped up the brushes with eletrical tape around the exposed parts. Works like a charm now.

[Raystar57]

If it comes back you know where to look.