520-8

[dkg520 509]

I have a 520-8 that was running great til last week.  I turn the key and get no power at all.  New battery installed and I have power to the starter but nothing when I turn the key.  I tried a new ignition switch but get the same result.  Anyone have any ideas on where I should start. Thanks for any help.

[gwest_ca-(File Mod) 11,069]

Download this file. Each circuit has it's own diagram making it easy to follow. They illustrate what it takes to make it work.

 

[Handy Don 12,277]

32 minutes ago, dkg520 said:

Anyone have any ideas on where I should start. Thanks for any help.

I always start with obvious connections--are they clean and tight?

Battery positive and negative?

Ground from battery to engine?

Connections to the ignition switch?

Connections to safety switches?

And, specific to the Onan-powered tractors, any visible damage or overheat evidence at the 9-pin connector that links the engine wiring to the tractor?

 

Then look for broken or frayed wires.

 

I’m not directly familiar with that model, but in your situation, “no life when trying the key”, I’d look for problems at the safety switches--disconnected wires or broken switches, for example. Clutch, seat, and PTO safeties can all affect start/run. Use the wiring guide to look for continuity and voltages as you trace the wires. I’m assuming you have a working volt/ohm meter and know how to use it, of course!

 

Take NOTHING for granted -- I even, sometimes, distrust a new battery until I’ve tested it.

[ri702bill 8,385]

Onan engine with the dreaded 9 pin Connector?? If so, there's a good place to look for apparent issues.....

[Ed Kennell 38,324]

52 minutes ago, dkg520 said:

I have power to the starter

If you have 12v to the starter it should be spinning.    If it is spinning and not engaging the flywheel, you need to clean the bendix.

[lynnmor 7,317]

You will have power at the big wire at the starter, check for power at the small blue wire when you turn the key to start. 

[Handy Don 12,277]

Sorry, this may be plug simple and I missed it.

Is the PTO disengaged? If not, no start!

(No need to ask how I know about this.)

[SylvanLakeWH 25,614]

6 minutes ago, Handy Don said:

Sorry, this may be plug simple and I missed it.

Is the PTO disengaged? If not, no start!

(No need to ask how I know about this.)

 

I've heard that some people may have, uhm, done that... 

[Ed Kennell 38,324]

Just now, SylvanLakeWH said:

 

I've heard that some people may have, uhm, done that... 

   Usually when you run out of fuel while mowing.   Carry fuel out and fill the tank and no start.    

[8ntruck 7,034]

3 hours ago, SylvanLakeWH said:

 

I've heard that some people may have, uhm, done that... 

Nope.  Not me.  Never ever.

[953 nut 55,389]

There is a 25 amp fuse in line from the battery (via the solenoid connection) to the ignition switch. It is near the battery and over the years acid fumes from the battery being charged will cause the fuse holder to begin corroding. This is likely to be the problem, replace it with a HEAVY DUTY 30 amp fuse holder.