Sudden Engine Shutdown

[MLJ1IA 2]

We have a 1996 520H Wheelhorse garden tractor that we have had for several years; well maintained and has always run well.  Was getting ready to push snow yesterday and started the tractor as usual. It fired right up and sounded great while warming up in the garage for about 10 minutes. Then the engine suddenly just died. When I tried to restart, it acted completely dead with no dash lights, no engine turn over....completely dead.  Battery checked and showed a good charge status. Spark plugs pulled and looked fine.  This morning, it started up again, sounded good but same thing happened after about 15-20 minutes. Has anyone else experienced this? I could sure use some ideas or suggestions on what the problem might be and where I might start looking to diagnose the problem (engine issue or electrical?). Seems like once it gets warmed up, something is sensing it to shut down completely. I have been following this forum for a couple of years and have found that there seems to be a lot of expertise and good advise out there. Could sure use some now.

[Maxwell-8 4,367]

Maybe low oil switch? 

[roadapples 6,983]

When it shuts  off, hold key on and wiggle wires to fuses...

[Handy Don 14,061]

@MLJ1IA, please give us an idea of your comfort and skill level in doing diagnostics on the machine so we can make suitable recommendations. Can you read and follow a wiring diagram, for example? Do you have an owner's manual handy?

 

The "completely dead" part make me think electrical, too. I'd start, as @roadapples suggests, with the connection between the battery/alternator and the ignition switch. This would explain no lights, no cranking.

 

The 520H has dash indicators and a switch for testing them. Were they working when the tractor was running? Did any lights come on before the shutdown?

Are engine and transmission oil levels good? (The oil low pressure or temp sensors can stop the engine, but won't kill all the power)

Are you off the seat and engaging the PTO? (safety switch will stop the engine and prevent restart but, again, won't shut off all power)

[gwest_ca-(File Mod) 11,474]

Look for signs of overheating at the white 9-pin connector near the battery.

 

[lynnmor 7,815]

Yep, #1 suspect is that 9 pin connector.

 

#2 would be the ignition switch.

 

The oil and temperature sensors only turn on warning lights.

 

Only the very early 520’s had a switch to check the lights, later models check when you turn the ignition switch.

[MLJ1IA 2]

THANKS SO MUCH to all for so many quick responses. It does seem to be electrical.  To answer Handy Don's question...I would by no means consider myself a seasoned mechanic, especially when it comes to electrical diagnostics. I haven't had to deal with any electrical problems to date on this 520H. I do have the owners manual. I also can read and follow schematics/diagrams decently. Thanks to gwest_ca-(File Mod) for sending the wiring diagram for download.  I will definitely check out the white nine pin connector.  When I started the tractor yesterday,  all the dashboard indicator lights did initially come on but two  random indicator lights stayed on longer than usual (air filter and Brake). Then, these two just randomly went off  and stayed off when I moved the tractor forward a few feet a couple of minutes before it died.   I took Roadapples advise this morning and tried jiggling some wires right behind the dash and down by the fuse box and the tractor started right up with dash indicator lights all running through their check for a few seconds and then all turned off as usual.  Tractor is running just fine this morning after that and I just finished moving snow and with it now back in the garage. So now, I guess I just have to figure out which of the jiggled wire/s is the issue and created the problem.  Again, I really appreciate you guys!!! We have a foot of snow on the ground with about 6 more inches forecasted for later in week. Really appreciate having my wheelhorse right now.

[Handy Don 14,061]

6 minutes ago, lynnmor said:

Only the very early 520’s had a switch to check the lights, later models check when you turn the ignition switch.

Good to know, thanks.

 

8 minutes ago, lynnmor said:

The oil and temperature sensors only turn on warning lights.

 

Of course. Duh

[Handy Don 14,061]

1 minute ago, MLJ1IA said:

THANKS SO MUCH to all for so many quick responses. It does seem to be electrical.  ...

Great.  

You'll find lots of posts here concerning that 9-pin connector. Most folk either replace it with new or else use a sturdier, waterproof equivalent.  

One of the vendors here, Wheel Horse Parts and More, carries direct replacements and the tool for getting the pins out. Replacing is not a hard job as long as you get all the wires in their correct places. Maybe a job for springtime.

 

[squonk 43,799]

That 9 pin connection should be eliminated from the surface of the earth. Joseph Lucas would be proud of that thing!