Z445 - Troubleshooting a starting issue

[PandDLong]

My Z445 started to become a challenge to start at the end of the mowing season - it frequently would do nothing when I turned the key. If I kept trying it would eventually engage the starter and fire-up. I estimate only 1 out of 6 attempts would actually engage the starter.

As part of my winter maintenance, I decided to fix this issue. I've done the following and the problem is worse as now it never engages the starter:

1. Fully charged the battery (smart charger says it is a-ok)
2. Cleaned up all the connections between battery and starter (including the grounds) by disconnecting/sanding lightly
3. Tested voltage and the ground is good

So, I am thinking it could be the solenoid, a safety switch or even the key ignition.

How can I narrow down the root cause?

I recall learning - many, many years ago - a simple way to test the solenoid but don't remember what it is - and maybe it isn't applicable to a mower.

 

[beenthere]

May I suggest a new battery. From the symptoms, it is time.

 

[RetiredCarGuy]

1. Have you checked for the voltage drop on all your wires? It could be a corroded connector that is internal and you can't see.
2. How old is your Z445?

 

[PandDLong]

May I suggest a new battery. From the symptoms, it is time.

Well the battery is a few years old so that could be the issue. I swapped it out for a 8 month old battery from my lawn tractor. No difference. At least the battery is ruled out as being the source of the problem.

 

[PandDLong]

1. Have you checked for the voltage drop on all your wires? It could be a corroded connector that is internal and you can't see. 2. How old is your Z445?

The Z445 is just about to turn 5 - it's been through 4 mowing seasons.

Corroded connector search - sounds like a good idea. Not being a guru with a multi-meter (and electricity) - I'll have to ponder how to do that.

Thanks for the suggestions.

 

[JD mower man]

It is a bad starter solenoid or a bad ground on battery. Most likely the solenoid. It's pretty comments problem. You can find it inline between the post batter cable and the starter motor

 

[PandDLong]

It is a bad starter solenoid or a bad ground on battery. Most likely the solenoid. It's pretty comments problem. You can find it inline between the post batter cable and the starter motor

I've cleaned up the ground connections and the voltmeter shows it as being okay. My gut tells me the solenoid too but wondering if there is a way to test it other than buying a new one...

 

[bertsmobile]

OK the routine goes a little like this.
Make yourself some long jumper leads out of say 5A wire with a female spade on one end and an alligator clip on the other and some with a female on both ends.
make some short ones with a male at both ends
I have not checked the circuit diagrams for your exact mower but this is my "no start " drill & as the name suggests I am a mobile small engine mechanic.

before you start, try to revolve the engine by hand slowly.
If it is really difficult to get over TDC then you need to adjust the valve clearances . Most no starts are valve problems not electrical ones.
Verify the earth contact by running a jump start lead form the _ on the battery to a good earth point on the engine ( oil drain plug )
Also verify the power lead by using a jump start lead from the battery to the + feed wire ( thick red one) on the solenoid and then to the starter by bridging the two heavy red wires on the top of the solenoid

Test 1 )
Aligator on the - battery terminal other end to the earth point of the solenoid.
Note if the solenoid has 2 small terminals at the base one will be - and the other + so be careful.
If it has only 1 then it will be + and the - trigger is via the case of the solenoid.
Problem gone, bad earth on solenoid or faulty safety swiches / relays.

A little note here is originally all the safety "no start" switches used to interupt the + switch feed to the starter solenoid.
However some cleaver Dick realised tou can do the same thing with the - feed and thus not have to worry about wires chafing & shorting out.

Test 2
Do similar with the + wire. leave the - jumper connected
starter spins then starter is OK

Test 3
find the start trigger wire on the ignition switch. Usually marked with the letter "S"
Run a jumper from there directly to the solenoid. Leave the - jumper connected.
Try to start at least a dozen times.
If 100 % then the starter switch is OK and the problem is in one of the safety switches

now is when the fun starts
The seat, PTO , Brake & gear change all have safety switches on them and most will have at least 4 wires.
One pair prevent the engne from starting ( normally closed ) and the other short out the magneto ( normally open ) and kill the running engine

So now one by one work out which pair of wires does what at each switch and use the jumper leads to bypass the switch.
Continue till you find the culprit.
Note exactly when each switch activates as oft you will get some wear in the end of the plunger just enough to prevent the switch from making full contact all the time

 

[PandDLong]

Bertsmobile - thanks very much for the detailed instruction.

I got called out of town for a few weeks, so this dropped off my list. I should get to it it this weekend and will let you know the outcome.

 

[Walt 2002]

Simple way, jump with a good set of jumper cables directly from a known good battery ground to a ground on the engine and directly from the positive of the battery to the starter terminal. Now if starter works OK, you know it is a wiring problem. Now use just one side of the jumper cables at a time to isolate if the problem is in the ground circuit or positive circuit. IF jumping with a small jumper wire directly from the battery cable connection on the starter solenoid to the small terminal on the solenoid makes starter work, you know problem is in safety switch/ignition switch circuit.

Note IF the solenoid has two small terminals, one will be ground, jump to the other one.

None of this helps, check valve clearance.

Walt Conner

 

[PandDLong]

Problem solved. It was the solenoid - I used the information provided to figure out it was definitely the solenoid. Replaced it and all is well.

The detailed information was useful as I needed to sort out enough of the wiring to know which terminal was which on the solenoid and test it directly.

I certainly learned a lot of new information about wiring which I am sure will be useful in the future (unfortunately). The tip that safety switches are typically on the -'ve circuit was a new one to me.

 

[bertsmobile]

Good to hear it all worked out before you ran out of hair.

And yes modern mowers are getting quite complicated.
The old days the starter circuit was a simple daisy chain and you could follow it from the switch all the way to the solenoid

Then they started to get clever.
For 50c more they could put a 4 pole solenoid in place of the 3 pole one.
That meant they could daisy chain the ground trigger in place of the 12 V trigger thus no more warrantee claims for burning mowers.
Then there was the voltage sensitive solenoid that won't fire unless it gets 9 - 11 V ( few of them ) thus no more warantee claims for burned out starter motors due to flat batteries or dirty terminals.
Next step was to fit a stack of relays so you could play with a + switch and/or a earth control wire.

Waiting in the wings is all black wiring to make it harder for idiots to bypass the safety switches and safety switches with inbuilt resistances or cross over switches to make it even harder to by pass the switches.
This is because the legislators are all God fearing Creationists who see it as their duty to legislate out stupidity.

Pieso electric seat switches are alresdy being fitted into cars to prevent theft and mostly kids accidentally starting them and these are also on the plate for mowers once they all go EFI which will be around the end of this decade.