starting by itself...

jagers20

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Okay folks, new member here, I have a very small-time business. i have two mowers, both with problems, but the main one that is stumping me is my Poulan 925ZX zero turn. It has a B&S engine that will start whenever the positive wire touches the pos post on the battery. ive checked the starter solenoid, and it is opening/closing as it should. this is the third solenoid though, and i'm curious if there's something in the system BEFORE the solenoid that is causing trouble. I'll explain. So right now,i have everything hooked up except the positive wire to the post. As soon as I touch it, it will try and start, no key at all, and it will start sometimes. when it does start, it runs for a few seconds and dies out. then trying to crank it back up, it will start (occasionally) but the starter will stay engaged and won't stop unless i unhook the cable from the positive post. It has a new solenoid, starter, clutch and carb rebuild. I have put money into it and it seems to be biting me in the ***. I don't know what the problem is, and I'm no master electrical gremlin chaser. Any input would be appreciated.
 

bertsmobile1

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Disconnect the power wire to the starter itself to prevent it from turning then hook up the battery.
On the bottom of the solenoid should be 2 wires.There are the trigger wires.
With the ignition turned off there should be no power to either of them.
IF there is power then the starting circuit has a short.
If there is ground to one of them the safety circuit has a short.
The + side goes from the fuse to the B terminal on the ignition switch to the S terminal on the ignition switch to the PTO switch to the Brake Switch to the trigger terminal on the solenoid.
The added safety circuit for ZTR's guns a ground wire to one lap bar to the next lap bar & then to the - trigger terminal on the solenoid

To save wire, the power feed to the mower is generally taken from the Power post on the solenoid.
Double check you have not run this wire to the trigger terminal by accident when you replaced the solenoid.
You will not be the first to have done this, it is a very common mistake.
The other happens with the mowers without the - circuit and a short jumper to make a better ground contact.
Because one side has a ring and the other a spade I have seen more than one person fit this wire from the power terminal to the + trigger terminal with the same result.
 

jagers20

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i'm going to try this. since i posted this, it has been in the shop twice more, a wire was fixed on the ignition switch, but the solenoid was replaced twice again. still has the same problem. starts up, works for a day or two after, then cranks, runs for about 5 feet, then dies and won't start up anymore
 

bertsmobile1

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OK,
You are there and we are all on the other side of the screen with nothing to go on but what you posted, which quite frankly is more than a tad confusing.

So to start with is this your wiring diagram, you will find it n page 62 of the owners manual which most likely you have not read
View attachment 36800

Now if we are all singing from the same song book,
1) what was replaced the solenoid or the relay or both ?
if the relay ( part 12 ) in the wiring diagram went short then the yellow wire would always be showing 12V so the solenoid ( part 13 ) would always be energised so the starter will always be spinning.

This was mentioned to you back on Nov 2 but when you failed to respond the assumption was you worked it out then never bothered to let any one know.
There is no excuse what so ever for a workshop to replace a solenoid twice unless the one they fitted was faulty.

Now back to the start.

Exactly what is happening with your mower because what you have written so far does no make much in the way of sense
 

jagers20

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what happens with it is that i get it back from the shop, it runs great for a day or two, then it will start up, run for a little while then die. i can then try and crank it and it will act like its getting no fuel. i'll take it back to the shop, they put a new starter solenoid on it and it works for a day or two...then repeat the process. it is getting fuel. i havent noticed it this time as much, but before i took it to the shop this last time,the starter would try and stay engaged and start. i would have to unhook the pos cable in order for it to stop. i havent noticed that this time, so it seems to be back around the starter solenoid being the only issue. i apologize for my terrible summarizing/describing skills.
 

bertsmobile1

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Well to put the boot on the other foot, we can not see , hear, feel or smell your mower.
We have nothing to go on but what you wrote .
as previously posted, the starter motor not turning off will 99,9999999% of the time be a faulty relay and not the starter or the solenoid.
It seems that the workshop you went to finally twigged to the fact it was a $ 2 relay and not a $ 30 solenoid and if they have any integrity they would not have charged you for multiple replacements of an item that was not faulty from the get go
In 5 years I have replaced 3 solenoids and all have been open circuit cause the contacts have burned out.
However if you hold the starter on till it starts to smoke you can weld the contacts closed, I have heard of this happening but am yet to actually see it happening.

If you intend staying in business I strongly recommend you find a new workshop cause the one you are using are incompetent .
Get yourself a can of carb cleaner and a red neon in line spark tester or better still 2 of them.
Plug them in and go mow, they can stay in there for decades with no adverse effects on the engine.
The next time it stops, crank the engine and check for red flashes , if you see red then quickly give the engine puff of the carb cleaner and crank again.
If it starts right up and either stops or continues running then you have a fuel supply problem.

If it turns out to be a fuel problem then prime suspect will be the cut off solenoid in the carb or as is most often the case, the wiring leading to it.

If you get no red flashes then you have an ignition problem.
This becomes a little more difficult as there are a few safety switches that can cause this.
There is also a bridge wire that runs between the two coils which has a diode in it and that is prone to failure.
Pull the wire off the coils and go mow again ( caution here as all of the safety features and the off position on the key is dissabled like this).
If the mower gives no more problems then it is the wiring.

More than once I have done a call out to a customer who had just had their mower serviced to find a mouse nest under the blower housing and chewed through insulation , so the workshop had not removed the housing to check the wiring and clean the cooling fins.
 
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Bert I see that you mention RED neon spark tester ??? Do you have a link for that ??

I have the OLD school briggs tester that we used from the school classes way back when we bought inventory on parts and the basic tools required for a dealership.... If I can find it along with 2 valve spring tools... I had to order a new one a couple years ago ............
 

bertsmobile1

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This is the tool I use down here & I get them form a local wholesaler
Sold probably 30 or so usually right out of the tool box when on site so I keep two in there now
https://www.gaspares.com.au/products/TOL517?q=spark%20tester&product_code=TOL517&per_page=&product_page=&search%5Bcategory_url%5D=

A bit pointless of me chasing up suppliers in the USA but if we have them down here then you lot must have them there only with bells & whistles and a full precision marching band.

IF not it is just a neon tube like we used to have on old timing lights inside a length ( about 2" ) of clear plastic tube with a length of copper core plug wire on each end.
Just a lump of heatshrink to hold the wire to the tube , so it beaks every now & then which gives me the oppertunity to make the wires longer.

For the commercial customers I wired in some flashing spark plug caps which I got form a local hot rod shop as a cheap clearance line .
They don't work as well cause you have to get off to see them flash, but they are happy with them.

Biggest problem is I keep on forgetting to remove them so I come back to do a service & find one has been there for 2 years :ashamed:

I got a std Briggs 3 prong one but they are heavy and tend to fall off and of course you can not see the spark jump from 6' away in daylight so it lives in the shop as does the plug on a clip jobbie,

These are even better when working on hand helds as again you can see the red flashes even if they are bouncing around on the bench, pole vice , trimmer stand or however you keep them things in one place.
 
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Thanks Bert how much do those cost ??? I have a friend in Perth and I looked the dealers up and there are a bunch over there...
 

bertsmobile1

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They wholesale for $ 14 Aust +10% GST, I usually sell them for $ 20.
Most mower shops have an account with Gripske's they are the biggest aftermarket parts wholesalers in OZ
I have a feeling that they are actually an Oregon or Prime Line product as Gripske are their Aust agents.
In Perth things are usually a little more expensive due to the freight costs.
Grippos also charge delivery for orders under $ 200.
 
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