JD Hydro 185 starter

philwhiz

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JD Hydro 185 starter won't turn over when I turn the key to start, I have bought a new key switch, didn't help, I replaced the solenoid on the starter, didn't help [didn't need one]. I can start the mower with a jumper from the battery the solenoid, what is between the key and the solenoid that I am over looking?
 

bertsmobile1

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:welcome:

Before you start, pull the spark plug & try to rotate the engine by hand.
No use checking the electrics if you have a hydraulic lock, seized engine or jambed belt overloading the stater motor.
Assuming the engine turns freely.

I like to start from the starter motor and go backwards .
Do the following 5 tests, regardless of the results from an or all of them as there can be more than one problem and you want to isolate where the problem lies.
Elimination of individual parts is important so you know by the end, the battery, solenoid & heavy power circuits are all in good order.

1) try to jump the starter motor directly from your car or truck.
Starter turns = starter good

2) do the same directly from the mowers battery
Starter turns = mower battery good
No turn = duff battery, recharge it & try again.

3) check for voltage ( + 12V ) at the solenoid trigger wire with the key in start position
3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )

4) leave ground jumper in place ( from step 2 ) & try key start.
Starter turns = power connection good but ground connection suspect ( most common )
Confirm it by trying again, extra ground removed
I run a secondary grouBefore you start, pull the spark plug & try to rotate the engine by hand.
No use checking the electrics if you have a hydraulic lock, seized engine or jambed belt overloading the stater motor.
Assuming the engine turns freely.

I like to start from the starter motor and go backwards .
Do the following 5 tests, regardless of the results from an or all of them as there can be more than one problem and you want to isolate where the problem lies.
Elimination of individual parts is important so you know by the end, the battery, solenoid & heavy power circuits are all in good order.

1) try to jump the starter motor directly from your car or truck.
Starter turns = starter good

2) do the same directly from the mowers battery
Starter turns = mower battery good
No turn = duff battery, recharge it & try again.

3) check for voltage ( + 12V ) at the solenoid trigger wire with the key in start position
3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )

4) leave ground jumper in place ( from step 2 ) & try key start.
Starter turns = power connection good but ground connection suspect ( most common )
Confirm it by trying again, extra ground removed
I run a secondary ground from the grounding bolt to one of the starter mounting bolts & paint over both with liquid electrical tape.

5) Remove the trigger ( thin ) wire / wires from the solenoid.
Ground one & bridge from the hot terminal to the other.
Starter cranks = solenoid good.
Solenoid is not polarity sensitive, BUT THE WIRING IS so make sure you remove the thin control wires.
Note a thinner wire on the hot terminal is not a control wire. It is the main power feed to the mower.


From here on things become very mower dependant as starting circuits are getting changed all the time.
Basically the power goes in a loop from the hot side of the solenoid ( saves wire, no other reason ) through the fuse to the B terminal on the key switch then to the PTO switch then to the parking brake switch then to the solenoid trigger switch , easy peasy after you grow the 3rd arm. Use a test lamp and follow the power.
However a lot of mowers with a 4 pole solenoid, run a secondary ground control circuit to the ground solenoid wire through the lap bars.
Then to stop this interfearing with the normal safety function of the ground kill, it goes to a relay with the ground as the switched connection.
These are a PIA as the + control wire to the relay comes from the power loop above and the ground side of the control comes via the normal cut out functions of the lap bars.
Be very careful because if you have a system like this and accidentally send 12V down the ground loop you can fry the magnetos on some circuits.nd from the grounding bolt to one of the starter mounting bolts & paint over both with liquid electrical tape.

5) Remove the trigger ( thin ) wire / wires from the solenoid.
Ground one & bridge from the hot terminal to the other.
Starter cranks = solenoid good.
Solenoid is not polarity sensitive, BUT THE WIRING IS so make sure you remove the thin control wires.
Note a thinner wire on the hot terminal is not a control wire. It is the main power feed to the mower.


From here on things become very mower dependant as starting circuits are getting changed all the time.
Basically the power goes in a loop from the hot side of the solenoid ( saves wire, no other reason ) through the fuse to the B terminal on the key switch then to the PTO switch then to the parking brake switch then to the solenoid trigger switch , easy peasy after you grow the 3rd arm. Use a test lamp and follow the power.
However a lot of mowers with a 4 pole solenoid, run a secondary ground control circuit to the ground solenoid wire through the lap bars.
Then to stop this interfearing with the normal safety function of the ground kill, it goes to a relay with the ground as the switched connection.
These are a PIA as the + control wire to the relay comes from the power loop above and the ground side of the control comes via the normal cut out functions of the lap bars.
Be very careful because if you have a system like this and accidentally send 12V down the ground loop you can fry the magnetos on some circuits.
 

Telesis

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Apr 19, 2017
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Are you hearing just a 'click' when you try it or is it completely quiet. If you are NOT hearing any click at all, please ignore this post and troubleshoot per Berts procedure. If you are getting a click, then look into installing one of these:

http://www.greenpartstore.com/John-Deere-Starting-Improvement-Relay-Kit-AM107421.html

One way to test is to measure the voltage where the purple wire connects to the starter assy when you are trying to start it(with the black meter lead grounded of course) and see what you are getting. If nothing, then procede per Berts. If you hear it click, take a small jumper wire and connect that purple terminal to where the + batt lead connects on the bottom of the starter and if it turns over, then you know you likely have a voltage loss situation. I think(and I'm guessing JD does too) it's more cost effective to install one of these relays than to replace every switch in the circuit.

I'm speaking with personal experience. I had the click problem with my JD 170 with a 14HP Kaw engine. I can bore you with the details if you'd like, but suffice it to say, this new relay basically minimizes any losses in the wiring/switches etc that lead up to the integral solenoid. If yours doesn't have a Kaw engine, then it likely has a different solenoid setup and this won't apply. I did this to mine a few seasons ago and it has started perfectly every time since without a single "click".

The existence of this kit(IMHO!) acknowledges that the Kaw starter/solenoid cannot tolerate much in the way of voltage drop in the line that ends up as the purple wire connected to the starter assy that activates the solenoid. Since this new relay coil draws very little current compared to the solenoid coil, it pulls in very easily and connects the local battery voltage on the starter terminal to the solenoid terminal where the purple wire would go with very short lengths of wire. As the ign switch and the other safety switch(es) in the circuit wear and connections aren't pristine as new, the relay will operate more reliably.

Something to consider.....
 

philwhiz

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Jun 18, 2017
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I have the Kawasaki engine also, but I looked at the electrical print online and it shows a purple wire but my trigger wire is Blue with a White stripe. I bought this mower in 1992 it mows and runs as well now as it did in the beginning. I am thinking that I will drill a hole in the dash and wire a push button switch, battery to trigger post on solenoid. I been using Gator clips from +battery to solenoid to start for the past 3 years!
Thanks for the info, philwhiz.
 
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