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I am having electrical problems. The mower won't start on its own battery that's fully charged, or if it does spin its only once before you get clicking. Also the electrical clutch will not engage and a quiet arching sound can be heard when trying to engage the PTO that I can't seem to isolate. I removed the Clutch and tested the pins and got around 4 Ohms which is supposedly fine. I then used a battery and wired it to the clutch and the two separate parts of the clutch do in fact lock as they are supposed to when voltage is applied. I even took it a step further and hooked it up to its electrical connector on the mower and while it was in my hand I could engage the new PTO switch and it will in fact lock up as it is supposed to. It is only when I bolt it on the crankshaft that everything falls apart. I've been poking at the electrical system and can test most parts of the wiring harness... I just am not a master at it and to be honest my brain is now fried and can't seem to backwards engineer what I think is a short to ground that sends voltage through the crankshaft and interferes with the operation of the clutch. Help?

Are you sure the battery is in fact good. Maybe should be load tested to make sure the battery has voltage and amps under load. From there need to clean the battery post and the wire terminals both were the hot wire connect to the battery and the solenoid, as well as the black wire were it connects to the battery and the mower frame. And if you are getting voltage from the clutch through the crankshaft the clutch is shorted and will have to be replaced.

IS there any resistance between the either two wire terminals and the coil's metal frame when the clutch is off the equipment ?

Yes. The positive clutch pin has some order of mega ohms between it and where the crankshaft would ride on the clutch... Guess that means there's a path for electricity to flow from the positive through the clutch to ground on the engine, otherwise it would read open right? It's really a nightmare because poulan absolutely loves those clutches. I can find them in various places for around $300.

Clicking sound is usually a bad battery. Solenoid kicking in and out.

Yes the battery is bad. But I am more concerned with the short. I can start the mower with my drill on the flywheel bolt in a pinch, but if my blades don't engage I can't mow. Thanks for taking time to stop by and try to help maybe it will help someone who stumbles across this. In my case What I gather so far is just the internals of my clutch are shorted to the housing which prevents it's from operating correctly. Unfortunately I've spent too much on this mower to justify another $300 on a clutch so it seems I'm just occupying my garage worth $1000 worth of scrap metal. I'm going to try and get inside the clutch since I've got nothing to lose at this point and see if I can't repair the short myself as I can solder and do repairs of that nature and if anything comes of it I'll post. Thanks again.

Very rare for them to short internally and still work.
HAve seen a couple where the wires have chaffed and shorted out against the housing but must times the wires break off where they are connected to the clutch.

Good point. Resistance between the pin an the housing while off of the mower tells me that there is a path there for electricity to flow, which would be a short I would think. Unless one of the pins is supposed to ground to the housing for any reason. It seems to explain why it works great anytime until it is physically bolted to the output shaft. Otherwise maybe it's possible something else shorted causing voltage in the output shaft....somehow affecting the clutch. I will say there's a notable oil leak the ends up on the clutch, I cleaned it the best I could when I pulled it off.

If the battery is really bad and doesn't have enough voltage to start the mower what makes you think it has enough to keep the clutch engaged? I know that automobile air cond. clutches need full voltage to stay in gaged so may be what is going on with the PTO clutch. Just my 2 cents worth.

That's a valid point. I have small car battery that I have been using and it has made no difference. That's really the only reason that makes me think it has enough to engage the clutch, seeing it is the battery I currently use in the car. It should be more than enough.

Also need to keep in mind that if at any time the battery voltage drops below 10 volts the voltage regulator on some mowers will shut down due to the internal switch that will open with low voltage. So a bad battery can cause all kinds of issues. And if the resistance from the wire to the housing is in M ohms I wouldn't lean too heavy on that reading because the leakage would be measured in milliamps. Have seen more than one battery that would start the mower but wouldn't keep the clutch engaged.

Noted. Thank you the Knowledge and advice. I will use it and see where it takes me and post any findings.

Although normally a meg ohm reading would normally be ignored, here with the clutch field fully insulted from ground (metal chassis) it does point to a potential problem. I would now remount the clutch and do the same tests to see if things change as the rotor is tighten down. And even just connect the +12 lead without the return ground lead and test.

As noted normally this clutches don't fail this way but anything is possible. I have these clutches to pull up to 20 amps and still work even though they are partially shorted. And yes I have seen a couple to be shorted to the metal casing or the rotor.

Note a clutch field reading of 4 ohms would mean the field would normally only pull 3 amps at 12v. This will not overload a good battery. As starter it self pulls 70+ amps when starting and as much several hundred amps in a stall situation.

Electrical problems can be tricky when it comes to bad connections and arcing shorts Some arcing shorts will only occur above a certain voltage potential. It is like the spark gaps I use here to protect my electronics. Normally they don't arc but as soon as voltage goes above a certain point they arc. Just this week a remote lightning strike triggered them.

Some bad connections can test good with DDVM but fail under normal amperage draw (ie drops out). This is where with problems like the OP we need to do voltage drop tests under actual loads. Testing not under load can give you some false readings. An example is one mower here about 7-8 yrs ago. This mower would just bump the starter solenoid. I went through the voltage drop tests under load and found one of terminals was just connect by one strand of wire. Off load there was the full 12v but as soon as I loaded the circuit it dropped out. That mower had been in three other shops locally and they could not find the problem. Problems like this does takes someone with the experience to find them at times.

For let's focus on the cranking problem first and find where the drop out is occurring. It can be the battery or simply a bad connection. Then we can go back to the electric PTO clutch later. Once the cranking problem is resolve it might just cure the PTO clutch problem too.

Also note you don't have to buy the mower's OEM electric PTO as Xtreme clutches are usually much more cost effective if it turns out that the PTO is bad.

And some problems can be regional specific. Here in 13 yrs I haven't seen a bad battery to crank an engine but not operate a PTO clutch but any is possible. Who would think an electronic calculator would add wrong but it happen on the Victor 600 series.

Thank you for your reply. I will absolutely do that and currently working on it now. Since you guys are so willing to help I want to add pictures but they seem to be too large to upload so I guess I'll continue to just describe it. Ok so I retested the ohms between the pins and the housing in both scenarios, once off the mower and once while bolted down. I also note the battery is also attached in the mower. I noticed while testing that if I wiggled the wire around my reading would change. In both places, bolted down and isolated, and depending on how I bent the wire around, the ohms would change between open, ~4ohm, and ~1-4 M ohms.

Ok so for the starting issue. That was initially the first issue I had with the mower. I have a faulty solenoid off the bat, I mean, it still works, but when you attach either post wire on it the whole stud spins and the contacts inside spins as well. This has spun and busted a piece of the plastic that is rather small out of the side of the solenoid and you can literally see inside of it.... But it works... but I know I need to replace it. So initially the folks that were selling it to me were starting it by jumping the solenoid So I decided to figure that out. I took apart all the wiring harness coverings and back traced the entire relay system to find out the issue was that there's a wire that runs though all the safety switches and relays that was bolted to the output side of the solenoid. I figured they needed power before the solenoid closed so I swapped it over and the key will spin the engine over now... wasn't starting but at least the ignition was working. I replaced the PTO switch with an OEM part because the old one tested bad. I also wire wheeled every single connection I could find, so they should be cleaned. all this didn't start it so I bought a battery charger with a 125 A jump feature and a recovery mode feature. I charged the battery... and it charged until the charger told me it was full. It would crank the mower a few spins over then die almost immediately.... So that is the situation with the battery. I hooked up the car battery and same thing... after beating my head on the wall about it I decided to learn to voltage drop test it and found that my connections from the battery terminal to the terminal wire was dropping like 3 volts so I dropped my fear of damaging the battery terminals and crunk on the bastards a bit to fix the voltage drop, and it did. It spun over until I got tired of spinning it over. I also wanted to add that I have looked at a ton of Xtreme clutches and they are better priced, but I cannot find a single one that says it will replace my model mower's clutch. I can't bring myself to spend even $100 on a clutch that doesn't definitively say it replaces my specific clutch. That is because I don't have the experience to just look at it and say it will work. If you could tell me that you know it will work then I will consider it. Also to note to start my engine you spin it clock-wise. My mower is a 950 zx model 968999507. according to this ereplacementparts.com web link. the part number for this clutch is 539133076. When I look up that part number I come up with a counter-clockwise clutch....so that's also confusing me. here's the link to the clutch on the ereplacementparts.com: https://www.ereplacementparts.com/clutch-p-1532574.html .


UPDATE: Figured we'd go back to the car battery for testing that way we know it has the volts and amps it would need. Battery was a little weak but it was starting the car fine yesterday, I Know I keep saying car but I want to clarify the automotive battery I'm using to test came out of my old mercury mountaineer so SUV I guess is more apt. The battery is less than a year old. I plugged it to the mower, tested the voltage drop and nothing was being dropped up to the solenoid or lost at the the ground of the engine block. I turned the key to the on position and enabled the PTO switch and the clutch never locked up. To verify the battery was doing its job I attempted to start it and got the engine to spin to the compression stroke but couldn't overcome the compression and stopped. I could bend the wire attached to the input side of the solenoid up and could get a better connection, but still was not enough to turn the engine over. I tested voltage drop on the output side of the solenoid while trying to start it and I am dropping 1 volt on the output post of the solenoid. That is a bit much, I think zero voltage drop at the post of the input side vs. 1 volt on the output post makes me think the internals of the solenoid aren't connecting well enough. Also want to note I tested the volts at the battery afterwards and it was 12.0 v. That's a bit low so I have it on a 6 amp charge for a bit to bring it back up.

Normally an engine shaft rotates CCW when viewed from the output shaft end (PTO end). A clutch/brake assembly is designed to rotate CCW when it
is standard mounted with it’s field assembly next to the engine and the shaft as the input.

Xtreme #: X0582

But Sears currently has the OEM 539133076 on sale.
https://www.searspartsdirect.com/product/69wnr1kw3y-0071-917/id-539133076

That idea never dawned on me. Thanks for the information StarTech now it makes perfect sense why I would need a CCW clutch. Also I literally sank 3 hours or more of sitting at this computer looking all over google for a new clutch at a reasonable price and this blows everything I found out of the water thanks again. Majorly helpful.

UPDATE: I ordered the new Clutch. Gonna be about a week. Still not %100 that mine is useless, But maybe Ill find out before I put the new one on and can return it. Truck battery is almost completely charged and ill see if the old clutch will lock. Somehow I still doubt it will.

MY normal means of diagnosing these sorts of problems is substitution or bypassing
So in your case I would try running a booster cable from the battery + directly to the starter + terminal .
If the engine does not crank run a second booster from the battery - to a good ground near the starter ( I usually use the oil drain plug ).
Note the starter draws BIG amps so you will get a big spark, for me the size of the spark is part of the diagnosis .
Still no joy I do the same using an external known good battery, directly to the starter .

Some times I might also run the jumper to the starter side of the solenoid to test the solenoid<> starter cable

Water wicks down into the cable and can totally corrode the copper in the middle of the cable and this cable will test 0 Ω with a meter but carry almost no current .

And of course it also tests the starter as you get corrosion, carbon accumulating in the brush housing so a goodly portion of the power just arcs across the bottom of the starter.

When it is all said & done you can go crazy doing the maths trying to work out what is and is not acceptable but all that is actually important is does it work or not work .

By far the biggest culprit is the ground cable for the above mentioned corrosion reasons and I could not count the number of them I have replaced then painted over the cable end & mounting bolt with liquid electrical tape to prevent repeat performances.

You seem like person who can think for yourself so I will not write up the full preceedure in a set by step fashion complete with the diagnostics of the results of each step.

As for the clutch I often fit wrong ones just so long as the connection is compatiable with the mowers wiring.
Apart from the plug, the major difference is the diameter of the pulley , the actual strength of the solenoid , the surface area of the plates & the length of the tube separating the two pulleys which is not all that important as the deck goes up & down.
Most now days are braked ( deck pulley locks still when turned off ) but some are not which is another difference.
Occasionally I have to fabricate a new anchor but down here clutches run fro $ 500 to $ 1200 ( AUS ) so it is worth an hour of labour

I agree that substitution is a great way to isolate electrical issues. It helps to keep things simple. Being relatively new to all this I end up in situations where something seems like it is working when jumped, But I'm unable to tell if that is what was intended or it is only half-functioning so to speak. So learning drop voltage has been quite helpful in the way that dropping even minimal amounts of voltage amounts to some kind of issue between the two points, whether it is damage to the wire or a poor connection. I do know that up to a half a volt drop is acceptable in starter circuits and things of that nature. Thanks for the info on clutch fitment I will keep those parameters in mind if I am working on a mower in the future with discontinued parts. Also those clutch prices are insane.... For that price I would probably find a propane smelter and try to find my own iron to cast into clutch parts, jesus.

On to the mower I've gained more confidence that the clutch is indeed no good. I set the meter for continuity and checked the clutch pins, they weren't open so that was a good sign. Next I grounded one pin of the multimeter to the ground on the block and then tested continuity to each pin. In that instance I got Beeps on both for a path for electricity.... meaning it has definitely shorted to the housing. Moving on I got a bit confused because I decided to retest the mower side PTO connections for voltage when engaging the PTO switch and wasn't getting anything. So I followed the connections to the 20 amp fuse, which was supposed to be 15 amps I believe, and it was blown as well as moderately melted. I removed it and just miraculously had a 15 inch fuse on the workbench so I popped it in there. To test the PTO clutch I just turned the key to the on position and engaged the PTO switch (obviously all the safety switches are engaged). With the key on there's no circuit issues anywhere, then when I engage the PTO, instantly pops the fuse, so that further tells me that the clutch is probably fried. In all of this testing I had the SUV's battery attached to the mower at 100% charge, with no voltage dropped up to the solenoid, or to the grounding on the block.

bertsmobile1 said:

Very rare for them to short internally and still work.
HAve seen a couple where the wires have chaffed and shorted out against the housing but must times the wires break off where they are connected to the clutch.

Click to expand...

You have a mid coil short to the clutch body that when grounded provides fewer turns, more current, less magnetism, so high current an no function untill the metal is not touching ground ( what electrical people call a floating ground). So the circuit is different when the frame of clutch has a ground.. I am surprised a fuse is not blowing when mounted and engaged. The less magnetism will not overcome the spring brake incorporated in the clutch which stops the blades when disengaged. You can repeat the test by "Holding in your hand..." testing with a ground wire also touching the one or the other of the metal frames to ground and repeat that the clutch then acts just as if mounted.

VRR.DYNDNS>BIZ said:

You have a mid coil short to the clutch body that when grounded provides fewer turns, more current, less magnetism, so high current an no function untill the metal is not touching ground ( what electrical people call a floating ground). So the circuit is different when the frame of clutch has a ground.. I am surprised a fuse is not blowing when mounted and engaged. The less magnetism will not overcome the spring brake incorporated in the clutch which stops the blades when disengaged. You can repeat the test by "Holding in your hand..." testing with a ground wire also touching the one or the other of the metal frames to ground and repeat that the clutch then acts just as if mounted.

Click to expand...

I believe it wasn't blowing a fuse because there was an over rated fuse installed and it was melting the fuse holder. It did blow today and upon inserting a proper fuse it instantly blows when I activate the PTO.

Clutch fuses are from 5A to 10 A depending upon which clutch is fitted.

bertsmobile1 said:

Clutch fuses are from 5A to 10 A depending upon which clutch is fitted.

Click to expand...

The one previously installed was 20 amps. I installed a 15 amp which immediately blew on engaging the PTO.

bertsmobile1 said:

Clutch fuses are from 5A to 10 A depending upon which clutch is fitted.

Click to expand...

The problem Bert is that most USA mowers only have a main fuse and not a separate PTO clutch fuse. When a mower does have PTO fuse it is usually 7.5 amp. MOst have a 15 amp main but some 20 and 25 amp mains.

I have seen PTO clutches to pull up to 20 amps and still operate but usually overtax the charging system so the battery get drained. I had one a couple years ago to refuse to accept the fact that his clutch was shorted even though it was melting the wiring at 18 amp draw. Later he came back bitching that I knew his PTO was but didn't replace it. Well he had me to replace it so I installed a Warner clutch then he raise cane because I listed it as a Warner on my bill and not a John Deere part. It was the same clutch just without the JD price tag. There is just no pleasing some customers. I should just charged him the JD price and fake the bill using the JD PN.

StarTech said:

The problem Bert is that most USA mowers only have a main fuse and not a separate PTO clutch fuse. When a mower does have PTO fuse it is usually 7.5 amp. MOst have a 15 amp main but some 20 and 25 amp mains.

I have seen PTO clutches to pull up to 20 amps and still operate but usually overtax the charging system so the battery get drained. I had one a couple years ago to refuse to accept the fact that his clutch was shorted even though it was melting the wiring at 18 amp draw. Later he came back bitching that I knew his PTO was but didn't replace it. Well he had me to replace it so I installed a Warner clutch then he raise cane because I listed it as a Warner on my bill and not a John Deere part. It was the same clutch just without the JD price tag. There is just no pleasing some customers. I should just charged him the JD price and fake the bill using the JD PN.

Click to expand...

It happens to the best of us. If I recall correctly in the manual of my specific mower the fuse was intended to be 20 amps. It's either that or 7.5 amps. The wiring diagram is slightly confusing. It shows a 20 amp between the battery pin of the ignition but also 2- 7.5 amp fuses in other places... Although I've been all through the wiring harness and not found any other fuses unless they are built into components.

If you check the continuity from the two clutch terminals and to ground and you get a continuity reading it has a bad clutch just replace it. Have you tried https://xtremeope.com for a clutch. Good quality and reasonable price.

$185.95 at xtreme clutches

Thanks guys for looking that up for me but someone found me one on sale OEM at Sears for $150. I have it ordered and on the way. Like I said though I do appreciate the help. Thanks