My 520 doesn't charge while mowing and then dies.

[BBredmower6059 0]

I've been having some problems keeping my 520 running this year.  My latest issue is sputters and then dies. I've changed out the voltage regulator (I think that's what it is called, I've dealt with this issue before) (Sits on top with 3 male prongs) Knowing it is not charging while running, I had the battery charged up before I started mowing today.  My mower started up and I mowed for probably about an hour with no real problems other than it's not charging the battery.  I stopped for probably 1/2 hour or so and then started again.  Still no charging as expected, but now the mower is sputtering and sounds like it's missing as I open the throttle.  I mow for awhile to see if it will smooth out and it doesn't, it eventually dies.  I grab the battery charger to start it.  I start it up and seems to run fine for 3-5 minutes and then it just dies. 

 

Am I on the right track with the voltage regulator? I get about 35 volts AC when it's running.  Can you test when it's not running with a volt meter?

 

[WVHillbilly520H 10,369]

to ,The regulator is probably the culprit for NO charge situation but the run for a few moments sputtering then dies is either a fuel/carb issue (especially if you use ethanol laced fuel) or an ignition problem (coil/ignition module), I have included some of the electrical diagrams, but if it's fuel related you'll need to replace fuel lines and filter, clean carb(if not completely pull soak and rebuild) then if you can't get pure gas treat the E10 with something (Sta-bil, Seafoam ect, Jeff.

[gwest_ca-(File Mod) 10,488]

On thing you can try with the engine not running.

Check the voltage across the battery lugs. Not the cables on the lugs.

Now move the red test lead to the DC+ terminal on the regulator. Should get the same reading.

If the voltage is different the wiring the charge current uses to get to the battery is compromised.

 

Garry

[Ed Kennell 35,616]

35VAC   at 3600RPM is the correct input into the Voltage regulator.   If the wiring checks Garry details above check out OK,  Then you should measure 13.4 VDC output from the regulator at 3600RPM.    If not, you may have a  bad regulator.   New doesn't always guarantee Good.

[520hC-120 136]

I had a similar problem with my 520h except it died and had no spark. So no guarantees but it may be your problem.

So next to your battery there will be a connector connecting two wires to other ones. What will happen is it will get dirty and cause malfunctions. What I did is just snip the wires from the connector, and used just wire connectors to join them. Make sure that they are the same wires connected or I’m sure more issues will arise. Hope this helps.

[BBredmower6059 0]

Finally got back at it tonight.  The ignition coil tests out at 3.80 ohms and secondary resistance is over 21K.  Looks like I found it!  Thanks guys.  Now where is the best place to order an ignition coil?

[WVHillbilly520H 10,369]

6 hours ago, BBredmower6059 said:

  Now where is the best place to order an ignition coil?

I just google the Toro/Onan part # then look for the cheapest option...whether eBay Partstree or other vendors try @boomers_influence he's an Onan guy as well @onanparts.com, Jeff.

[520hC-120 136]

I have a brand new coil for a 520h 

PM me if you’re interested 

[boomers_influence 106]

club

the original P coil ( 166-0761 ) is held in by 2 bolts that are 180 degrees apart

it' s specs are 2.9 -3.6  ohms on the primary,

14,500 to 19,800 ohms on the secondary.

 

the replacement onan coil ( 166-0820 ) needs a special bracket to mount it.

the primary is the same at 2.9 to 3.6 ohms.

the secondary is HIGHER, 20.600 to 21.000 ohms.

 

thank you. boomer