voltage regulator on Onan P220

[cheesegrader 433]

So, along the lines of fixing one problem and creating a worse one....

 

I had to replace the fuse holder on yet another 520.

The 25 amp holder was melting, although the fuse was still good.

In the process of cutting things out, my wire cutter touched the metal on the hood tower.

Sparks!

Now that the fuses are back in, it won't start.

Starter engages, but it won't fire.

Volt meter says 10.5 volts, battery is a month old.

My theory is that I fried my voltage regulator.

Is this a good guess, and how can I prove it (short of just spending the money and replacing it)?

[cheesegrader 433]

Sorry.

Can the moderators please move this to the electrical forum where I meant to put it.

Maybe I shoud just give up today, and have a few adult beverages.

[Ed Kennell 35,769]

The voltage regulator is not needed in the spark circuit on the p220 Onan.  With the ignition switch on you should have  12v at the + coil post. If not, check battery,  the seat switch, the PTO switch, the 20 amp fuse, and the ignition switch.  Those are the components in series in the spark circuit.  If you have 12vdc at the + coil, it could be the coil or the  ignition  module or the spark plug.

 

BTW, 10.5 is too low ....charge the battery first.

Edited March 15, 2015 by ekennell

[rmaynard 14,897]

It sounds like maybe you had those adult beverages before you started cutting wires without disconnecting the battery.

 

If the battery is only reading 10.5 volts, try charging it with a battery charger for a couple hours.

 

I would look at the wiring diagram in the demystification guide for the "spark" circuit and determine where you are having your problem. As said above, the regulator has nothing to do with spark. If there is no voltage to the coil, then something in that circuit is open. If you do have voltage to the coil, then either the coil itself or the trigger module under the flywheel is the culprit.

[cheesegrader 433]

Yeah, I know.

Disconnect the battery first--unless you are in a real hurry, and just have this one simple thing to do.  Duh!

I asked about the Voltage regulator because 1)I thought that was where the sparks were flying and 2) I thought it provided some short circuit protection, but now I see only for the B+ terminal.

Just what I needed before before a 3-week work trip.  Maybe it will all just be better when I get back.

[Cable 179]

I think you have gotten some good advice above so I won't try to add to it. 

 

There is one thing that all 520 owners from 1990 on can benefit from and that is covering the fuse block.  The fuses get dirty and moisture is added which causes corrosion. Then the fuse block plastic melts.  On a healthy fuse block I recommend giving the fuses a good burnishing by inserting each one and removing them at least six times.  Blow it out with compressed air. Glenn Pettit makes a cover for the 520 fuse blocks that keeps the dirt and liquid water out. I have one on each of my five 520Hs.