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seuadr

520H cylinder heat temp switch - safety?

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seuadr

So, i got the new motor to fire over by bypassing straight to the coil, which means one of the safeties is out, or i have a bad relay.

 

looking at the schematic:

 

image.png.0580978b5ecaa7dec1b8c2e2b647e3b8.png

 

i'm wondering if the heat temp sensor provides ground to pin 12 of the idiot lights? looks like those fo all the way around to all of the relays and that sensor broke when i installed it (well, technically when i pulled the harness tight a few mins later..) my seat switch has been gone for i don't know how long, it was long gone when i got the tractor. the neutral switch seems to work - i show continuity when i close it in place, and none when i open it. i haven't gotten in to test the PTO switch, i can't actually get at it when the battery is in place - but i came in the house to take a look at the schematic and now i'm wondering if it is the head temp sensor - i initially thought it was just an indicator light? am i wrong?

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Tractorhead

It seems that some of the Idiot lights have a feedback for the power to the Kill relais, to prevent the start process.

 

i dunno exactly how the checklight dash is connected internally,

but i guess also the hydro temp and some other switches will affect to it what makes sense imho.

They try to protect the Engine by preventing startup without right conditions and even indicates that by a checklight additionally.

 

so the simplest way i think is release the lightdash, that you be able to measure on it

and check each part for it‘s function there by voltage tracing.

 

Edited by Tractorhead

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Handy Don

This unit has the extra relay that "assembles" the inputs of the safety switches (Kill Relay on the diagram) to prevent current to the coil (running). Switch Relay on the diagram keeps current away from the Start relay (starting). To my knowledge, the indicators are only indicators and have no effect on the start/run--that's the point of the relays.

Yeah, complicated!

Edited by Handy Don
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Chestnut

Wheel horse published a "demystification guide" - available on this forum, I think in manuals. It has a simplified wiring diagram that should help in tracking down the issue. I've attached the page for the '91-'97 520H. 

If I read it correctly when the switch is in start the current goes direct from the battery through the 25 amp fuse, the ignition switch, the seat switch  (yours is bypassed), the kill relay, to the coil.

Demystify 520H.pdf

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seuadr
2 minutes ago, Chestnut said:

Wheel horse published a "demystification guide" - available on this forum, I think in manuals. It has a simplified wiring diagram that should help in tracking down the issue. I've attached the page for the '91-'97 520H. 

If I read it correctly when the switch is in start the current goes direct from the battery through the 25 amp fuse, the ignition switch, the seat switch  (yours is bypassed), the kill relay, to the coil.

Demystify 520H.pdf 270.53 kB · 0 downloads

Thanks, that is the guide i took the screenshot from.

 

Looks like i need to test some switches, ultimately. Gotta rig up the battery to be hooked up temporarily outside the battery box to test the pto switch. I suspect that is the one, as it is pretty much the only one i have not tested.

 

That said, while i know the seat switch is gone, I don't know where it was bypassed, so swapping motors may have disturbed that "fix"

 

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Chestnut
2 minutes ago, seuadr said:

Thanks, that is the guide i took the screenshot from.

 

Looks like i need to test some switches, ultimately. Gotta rig up the battery to be hooked up temporarily outside the battery box to test the pto switch. I suspect that is the one, as it is pretty much the only one i have not tested.

 

That said, while i know the seat switch is gone, I don't know where it was bypassed, so swapping motors may have disturbed that "fix"

 

I couldn't get a full page screenshot of what I referenced, but it's a much-simplified diagram.

 

Screen Shot 2021-04-11 at 6.09.47 PM.png

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seuadr

Well yhe PTO switch appears to be good. The more i dig into this the more i question some of the "fixes" i am pretty sure my disturbing the wire probably broke one of these fixes.

 

I suspect I'll be doing some rewiring to replace some of these connectors.

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gwest_ca

p7-99 ign.jpg

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seuadr

Thanks, the kill relay seems to not be closing, but the ground wire reads good to ground - I don't seem to have any voltage on the brown wire, which is why i was checking safeties.

 

Found the seat switch bypass, appears to be good. Pto switch looked like it had bad connectors which i thought was the problem but nope. 

 

At this point i guess i just need to trace the voltage until it stops!

 

 

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gwest_ca

 

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Tractorhead

Check the Wire route where the Switching relay acts.

get a Voltmeter and check all this points to ground.

Voltage have to be checked in idle with disengaged pto and in neutral By switch ignition to on

 

check between:

port B on keyswitch to ground - there shall be Battery voltage be measured, if fail the 25A fuse or Fuseholder be suspected

Keyswitch port I from orange wire to ground - if fail Keyswitch is suspect

next is from orange wire on switch relay to ground = if fail wire somewhere interrupted cutted or defect ( broken).

 

next is from dark green switching relay to ground  if fail check the coil lines on this relay 

they must be both same level to ground if that is ok, the relay contacts be suspect.

To test this you can also simply remove one of the coil wires from that relay, the relay will not switch.

If the relay switches by reconnecting this wire, the coil path is somwhere wrong.

 

- To continue test remove one of the both wires from relaycoil and try again, if no

 

Next is from purple to ground if fail the PTO Switch is suspect

 

next is at least brown to ground if fails check the Seatswitch it shall be shortened to test if all is ok with Seatswitch, 

engage a gear and than recheck between brown and ground, if fail the neutral switch is suspect.

 

that is the basic test to find quick the antichrist in your Tractor.

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seuadr

i'll be able to get at this today after work. the more i think about it, the more i suspect the neutral switch. 

 

i have the foot control i just installed, but, i left the hand control and the switch in place both so it is easy to revert if i don't like it or whatever, and so that i could leave the arm in for the safety switch. I may end up having to do something different. i'm not completely in love with the idea of eliminating the switch - the seat switch i opted not to replace because i have a stationary attachment that i can't use if the seat switch is in play - but this one feels a little more meaningful. 

 

perhaps not a bad idea to just order both switches and replace them - these ones look to be original from 1993 or so, i think i got my mileage out of them :D

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peter lena

@ seuadr , read your wiring related issue, just thought I would send related cooling help pictures that would enhance your twin cooling ,   https://www.google.com/search?sxsrf=ALeKk02yBDhDzwbVDZmt1Lgeed1HeKihxQ:1618246287226&source=univ&tbm=isch&q=wheel+horse+belt+guard+air+holes&sa=X&ved=2ahUKEwioi--YlfnvAhWtElkFHfCbAHAQjJkEegQIBxAB&biw=1024&bih=625#imgrc=-IsNCFYPmX078M   just an idea in view of all the other work you have done , pete

 

 

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seuadr

So my dumb ass forgot to hook the wire that powers the ignition from the R/R up. On the old plug it was hooked in through the starter solenoid.. on the new engine the starter solenoids in the opposite side of the motor. It was hanging there with a plug all ready for me to plug it in...😆

 

 

 

Edited by seuadr
Going to upload ti youtube
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seuadr
1 hour ago, peter lena said:

@ seuadr , read your wiring related issue, just thought I would send related cooling help pictures that would enhance your twin cooling ,   https://www.google.com/search?sxsrf=ALeKk02yBDhDzwbVDZmt1Lgeed1HeKihxQ:1618246287226&source=univ&tbm=isch&q=wheel+horse+belt+guard+air+holes&sa=X&ved=2ahUKEwioi--YlfnvAhWtElkFHfCbAHAQjJkEegQIBxAB&biw=1024&bih=625#imgrc=-IsNCFYPmX078M   just an idea in view of all the other work you have done , pete

 

 

oddly enough, this motor seems to run cooler on the rear cylinder? of course, i've only had it running for a little bit, so, that may change. I gotta look into the quality of spark (even though the plugs and wires are new, the coil is not) to make sure it isn't an issue with the timing.

 

this motor seems to move a LOT more air than the P220 also - the whistling on the linked video (if it comes through) is the air blowing through the fan shroud out the back.

 

pretty excited about that. :D

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Tractorhead

Congrats 👍

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