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Model: 917.289071

Owner dropped it off with me asking me to fix it. Said it wouldn't start and now will not crank.

I can get it to turn over and start by giving it fuel (the carb is dirty) and using a screw driver to short the post on the solenoid.

Turning the key over does nothing.
The parking break is applied, blades disengaged.

I am wondering how to temporarily bypass the safety's or what checks you would do now.
The seat, parking brake, and blade safety electrical connectors are 4 wires. I am guessing the two white wires on each of these plugs are the safety but I am not sure.

Hexxus said:

Model: 917.289071

Owner dropped it off with me asking me to fix it. Said it wouldn't start and now will not crank.

I can get it to turn over and start by giving it fuel (the carb is dirty) and using a screw driver to short the post on the solenoid.

Turning the key over does nothing.
The parking break is applied, blades disengaged.

I am wondering how to temporarily bypass the safety's or what checks you would do now.
The seat, parking brake, and blade safety electrical connectors are 4 wires. I am guessing the two white wires on each of these plugs are the safety but I am not sure.

Click to expand...

White ones will be the kill switches and are all ground circuits which ground out the coil.
The other coloured ones will be the 12V trigger to the solenoid.

So this is a sort of standard procedure I use for "won't crank" situations.


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 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.

check below

bertsmobile1 said:

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.

The engine turns over and starts.

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 )

Will test. The solenoid is a 4 wire. Two main top post and two smaller wires on the side, one white, the other an unknown color.

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.

What ground wire from 2) ?

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.

trigger wires on this solenoid are the two smaller wires right?


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.

Click to expand...

Pull the 2 small wires off.
Jump from the battery wire on top to one terminal and from ground to the other.
Solenoid should close & starter should turn.
If not solenoid is duff.

Check the two small wires, you should have ground on one and 12V on the other with the key in the start position, parking brake on & PTO off.
If you have ground, check it again key in the off position.
If you still have a ground then it is not switched ( makes things easier )

Now for the fun bit.

The back of the key switch will have some letters on it
G = Ground
B = Battery ( 12 V 0
M = magneto ( must never have voltage )
S = Start ( goes 12 V in start position )
A = Alternator ( gets the voltage back from the alternator )
L = Lights ( this is either a ground or AC depending upon wiring )

There might be some other, A2 L 2 ignore them for now.

Pull the plug off the switch.
Make a short jumper with 2 spades on it and jump B to S , remember the plug is a mirror image of the switch so dont cross the wires.

Now you can follow the cranking circuit from the S terminal through the PTO switch then through the parking brake switch down to the solenoid.
Some were there will be a brake in the flow .

Updates coming.

Pulled the wires off and ran two from a battery to test the solenoid. I clicked and the mower turned over.
I was still having a fuel issue but once I fixed that the mower starts and runs. Can be killed with the key.
I do not have voltage on the two small solenoid wires.
I took apart the ignition switch and cleaned it but that didn't help.

While trying to fix it today I think the solenoid gave up. I was testing it again, it was clicking but wasn't engaging the starter.

Cranking circuit goes from the S terminal to the PTO switch to the Parking brake switch to the solenoid.
It is a daisy chain so any brake in the chain = no juice at the solenoid.

I can not find a wiring schematic, but the parts list does not list a relay so is one of the trigger wires always ground ?
I usually pull the plug off the key switch and jump the B & S terminals with a short wire fitted with spades at each end.

And despite the 16,000,000 U tube videos telling you that the seat switch is the work of the devil and must be disconnected just to prove you are a real man,,, it is not in the cranking circuit so leave it alone.
Pull the key switch out and on the back are tiny ( and I mean tiny ) letters B-S-M-G-A-L + sometimes a few more.
They got to exactly where the letters suggest.

It was the damn fuse... I am guessing the owner tried turning it over and over and over and over before bringing it to me and that blew the fuse. They said it WAS turning over but wouldn't start and NOW will not turn over so gosh I suppose I should have checked there first.


I found it out was the fuse but jumping those pins like you said. I didn't have power on that cranking circuit so I started following that red B wire and it led to a small black box that was attached to the inside of the frame that was covered in dirt, hiding.

Excellent.
Now enjoy the beers your mat is going to provide you.