A non internet savvy acquaintance asked me to help diagnose a fault on a
ageing but impressive diesel ride-on by John Deere, and it occurred to
me others might know these brutes better than I, so asking the question.

When I arrived it was 'not going' and after a while he diagnosed that
the fuel lift pump wasn't working. we hotwired that to te batery and it
spewed diesel all over the lawn, so we thought fuses and so on.

All we could find were intact.

Then I noiced that when he hot wired the pump, the solenoid that
operates the fuel cut off also worked. There was a bit of coat hanger
around it 'what's that for' 'Oh that burn out ages ago: I use the wire
to hold it open and remove it to stop the engine'
'well its working now' I said.

Then we decided that in fact the reason it had been working at all, was
on accoiunt of the tank being full enough of diesel it didn't need the
lift pump and that had in fact stopped working at the same time as the
solenoid. Confirmed by filling the tank up, upon which it ran just fine.

additionally when the power was applied to the pump/solenoid a relay
somqwhere also clicked.


On the mower there are the usual plethora of safety sensors - bum on
seat switch, foot on brake switch, etc. etc. And two boards - one
heavily weatherproofed containing discrete electronics and a lot of
dodes and resistors, tow relays and an IC, which looks to me like some
kind of interlock logic, and another one with two fuses on it and a few
more bits and pieces. Both have masses of wires going in and out..

I am guessing either a relay has burn out on one of the boards, or that
asafety sensor is OC. It would make sense would it not to put the lift
pump and fuel solenoid on the same circuit so that one could reliably
cut the engine in case of any safety violations..

But am at a loss to know how further to proceed..

Anyone worked on these or similar, before? Anyone gotta circuit diagram?

I have to say quite irrelevantly that the little 3 cylinder diesel is a
gem. I think is 25bhp of beautifully balanced 'chug' power.


--
Ineptocracy

(in-ep-toc-ra-cy) €“ a system of government where the least capable to lead are elected by the least capable of producing, and where the members of society least likely to sustain themselves or succeed, are rewarded with goods and services paid for by the confiscated wealth of a diminishing number of producers.

The Natural Philosopher used his keyboard to write :
A non internet savvy acquaintance asked me to help diagnose a fault on a
ageing but impressive diesel ride-on by John Deere, and it occurred to
me others might know these brutes better than I, so asking the question.

When I arrived it was 'not going' and after a while he diagnosed that
the fuel lift pump wasn't working. we hotwired that to te batery and it
spewed diesel all over the lawn, so we thought fuses and so on.

All we could find were intact.

Then I noiced that when he hot wired the pump, the solenoid that
operates the fuel cut off also worked. There was a bit of coat hanger
around it 'what's that for' 'Oh that burn out ages ago: I use the wire
to hold it open and remove it to stop the engine'
'well its working now' I said.

Then we decided that in fact the reason it had been working at all, was
on accoiunt of the tank being full enough of diesel it didn't need the
lift pump and that had in fact stopped working at the same time as the
solenoid. Confirmed by filling the tank up, upon which it ran just fine.

additionally when the power was applied to the pump/solenoid a relay
somqwhere also clicked.


On the mower there are the usual plethora of safety sensors - bum on
seat switch, foot on brake switch, etc. etc. And two boards - one
heavily weatherproofed containing discrete electronics and a lot of
dodes and resistors, tow relays and an IC, which looks to me like some
kind of interlock logic, and another one with two fuses on it and a few
more bits and pieces. Both have masses of wires going in and out..

I am guessing either a relay has burn out on one of the boards, or that
asafety sensor is OC. It would make sense would it not to put the lift
pump and fuel solenoid on the same circuit so that one could reliably
cut the engine in case of any safety violations..

But am at a loss to know how further to proceed..

Anyone worked on these or similar, before? Anyone gotta circuit diagram?

I have to say quite irrelevantly that the little 3 cylinder diesel is a
gem. I think is 25bhp of beautifully balanced 'chug' power.

You will possibly find a circuit diagram on the internet somewhere and
you can only make any progress with one. Failing that, find one of the
US mower web forums, and ask for a circuit diagram there.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk

"The Natural Philosopher" wrote in message
...

A non internet savvy acquaintance asked me to help diagnose a fault on a
ageing but impressive diesel ride-on by John Deere, and it occurred to
me others might know these brutes better than I, so asking the question.

When I arrived it was 'not going' and after a while he diagnosed that
the fuel lift pump wasn't working. we hotwired that to te batery and it
spewed diesel all over the lawn, so we thought fuses and so on.

All we could find were intact.

Then I noiced that when he hot wired the pump, the solenoid that
operates the fuel cut off also worked. There was a bit of coat hanger
around it 'what's that for' 'Oh that burn out ages ago: I use the wire
to hold it open and remove it to stop the engine'
'well its working now' I said.

Then we decided that in fact the reason it had been working at all, was
on accoiunt of the tank being full enough of diesel it didn't need the
lift pump and that had in fact stopped working at the same time as the
solenoid. Confirmed by filling the tank up, upon which it ran just fine.

additionally when the power was applied to the pump/solenoid a relay
somqwhere also clicked.


On the mower there are the usual plethora of safety sensors - bum on
seat switch, foot on brake switch, etc. etc. And two boards - one
heavily weatherproofed containing discrete electronics and a lot of
dodes and resistors, tow relays and an IC, which looks to me like some
kind of interlock logic, and another one with two fuses on it and a few
more bits and pieces. Both have masses of wires going in and out..

I am guessing either a relay has burn out on one of the boards, or that
asafety sensor is OC. It would make sense would it not to put the lift
pump and fuel solenoid on the same circuit so that one could reliably
cut the engine in case of any safety violations..

But am at a loss to know how further to proceed..

Anyone worked on these or similar, before? Anyone gotta circuit diagram?

I have to say quite irrelevantly that the little 3 cylinder diesel is a
gem. I think is 25bhp of beautifully balanced 'chug' power.



Using the model and serial number JD will (If asked nicely) furnish a manual
and diagram
Otherwise several pics of the machine and offending parts will usually
suffice emailed to the Tech dept