520H Safety Interlock

[tiggercl 28]

Chaps,

520H - If the engine is running, PTO engaged and operator seated, should the engine quit if the 'park brake' is then applied and the seat vacated? (PTO still engaged..)

Cheers,

Paul

[sorekiwi 761]

Gidday Paul, I'll have to look at a wiring diagram to be sure, but I know if my PTO is engaged and I leave the seat the engine stops. On my bumpy yard some of the bumps are big enough to bounce the seat off the switch causing the motor to cut for an instant.

I've never tried the combination of setting the brake, leaving the PTO engaged and leaving the seat.

What year is your 520? The wiring is slightly different from year to year.

EDIT:

Just looked at the schematics in the "Demystification Guide" (available in the "Files" section of this site). It looks like on all 520's the switch on the handbrake is just for turning on the warning light on the dash. The spark circuit is only influenced by the interaction of the PTO switch and seat switches.

So to answer your question - if the PTO is engaged, AND you leave the seat, the motor should stop, whether the handbrake is applied or not.

[zieg72 209]

Yes, when leaving the seat with the PTO engaged the 520H or any should die. My 269H, 416H all acted the same way with the seat sensor hooked up, parking brake or not.

[tiggercl 28]

Gidday Paul, I'll have to look at a wiring diagram to be sure, but I know if my PTO is engaged and I leave the seat the engine stops. On my bumpy yard some of the bumps are big enough to bounce the seat off the switch causing the motor to cut for an instant.

I've never tried the combination of setting the brake, leaving the PTO engaged and leaving the seat.

What year is your 520? The wiring is slightly different from year to year.

The 520H is a 1995 model. All the pre start safety interlocks and lights work (motional control, PTO, seat switch etc.). Lifting off the seat will stop the engine regardless of PTO position etc. with park brake 'off'.

The 73501 operator manual does not state that the engine should stop when lifting off the seat with the park brake engaged (and PTO engaged?).

Paul

[TT-(Moderator) 1,162]

I didn't look at the schematic, but it sounds like they want the parking brake applied before the operator leaves the seat. (perhaps someone got run over by their own tractor? )

With the PTO engaged, the engine should stop when dismounting - regardless of the parking brake position.

[tiggercl 28]

Gidday Paul, I'll have to look at a wiring diagram to be sure, but I know if my PTO is engaged and I leave the seat the engine stops. On my bumpy yard some of the bumps are big enough to bounce the seat off the switch causing the motor to cut for an instant.

I've never tried the combination of setting the brake, leaving the PTO engaged and leaving the seat.

What year is your 520? The wiring is slightly different from year to year.

EDIT:

Just looked at the schematics in the "Demystification Guide" (available in the "Files" section of this site). It looks like on all 520's the switch on the handbrake is just for turning on the warning light on the dash. The spark circuit is only influenced by the interaction of the PTO switch and seat switches.

So to answer your question - if the PTO is engaged, AND you leave the seat, the motor should stop, whether the handbrake is applied or not.

All sorted! The purple and the green wires on the PTO micro switch were the wrong way around. This particular model has individual 'spades' on the wires instead of the plastic moulded offset 3 spade style plug.

Thanks !

Paul

[SAM58 30]

If you want it to keep running with the blade engaged when you get off the seat, bypass the safety switch on the seat and it should fix.

[meldred40 1]

Hello, I need help with my 1988 520H.  I just replaced seat safety switch and the PTO switches.  When PTO is ON and I get off of seat, the engine does not shut off.  I have a young son and need the safety mechanism to work.  Any ideas or suggestions?

 

Thanks,

Mike

[gwest_ca-(File Mod) 11,492]

See if this helps

Keep us posted on your progress.

 

Garry

[meldred40 1]

Thank you.  I sure will.

[boovuc 1,090]

When I was out getting soaked earlier this evening bucketing the slop off the driveway, I tried something on my 1991 520. (I read this thread earlier in the day and wanted to confirm). I could leave the PTO engaged with the parking brake set and get off the seat without it shutting off. With the brake NOT set and the PTO engaged, it shuts off when I leave the seat.

PTO is running the loader pump. Are their differences between the safety switches/relays from the early to later model 520's? I didn't look at my 520 schematic yet.