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Simplicity mower blades engage sporadically.


wmarlowe's Avatar
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07-16-08, 09:23 PM   #1  
Simplicity mower blades engage sporadically.

Hi Everyone,

I have a Simplicity riding mower (rear engine). It is one of the Coronet series Mfg. # 1693307.

When the pto switch is engaged, the blades will sometimes engage and sometimes not.

The pto switch has been replaced and yet the problem persists.

Would appreciate any help. Thanks.

wmarlowe

 
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rogerflies's Avatar
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07-17-08, 12:39 AM   #2  
According to the manuals I looked at here:
http://www.simplicitytechpubs.com/te..._submit=Search

your mower has an electric clutch. The fact that it works sometimes indicates the coil is still good. Since you've replaced the PTO switch, the most likely cause is the seat switch. It prevents the electric clutch for the mower from being engaged with the seat empty.

The manuals don't have a wiring diagram, but the parts diagram suggests the switch should be closed with the seat down.

If that's not it, it's probably something loose in the wiring. That'll be a little harder to locate, but you can use an ohmmeter to read the continuity as you move the harness and connectors around.

 
Fisher40037's Avatar
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07-17-08, 06:35 AM   #3  
Without seeing the machine, I would see if the clutch is adjustable, and if so, adjust it. Also I would check the
voltage at the battery with the engine running, a weak battery
and a weak charging system can give you problems like this too.



Fish

 
rogerflies's Avatar
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07-17-08, 09:27 AM   #4  
The only adjustment I've ever seen on an electric clutch is for the brake that stops the blade when the clutch is disengaged. It's metal-to-metal contact between the drive rotor and the driven disc, and there's almost no slip when the clutch engages. These clutches are incredibly tough and reliable.

Low voltage could cause problems with the electric clutch, but it would have to be so low that you'd probably be having problems starting the engine, too.

My bet's still on the seat switch.

 
Fisher40037's Avatar
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07-17-08, 10:05 AM   #5  
Well here is a link someone else posted on another site that
shows the adjustment.

http://www.lawnsite.com/showpost.php...90&postcount=2

 
rogerflies's Avatar
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07-17-08, 03:31 PM   #6  
That's the adjustment for the brake that stops the blade. I've had clutches that worked fine with air gaps of 0.060", but the brake didn't work at all.

Referring to the picture from your link:

Part 1 at the top is the coil. It fits inside the drive rotor (part 4). It's supported by a ball bearing on the crankshaft, and it can move around a little bit.

Below that is part 5, which is really three pieces: The outer piece with three lobes is the stationary part of the brake. Inside that is the driven disc. At the bottom is the pulley for the mower belt. The driven disc is attached to the pulley by the three leaf springs you see at an angle in the center of the disc. The pulley is supported by another ball bearing on the crankshaft, since the disc and pulley don't always turn.

When the coil is energized, the driven disc snaps toward the drive rotor, which holds it VERY tightly because of the powerful magnetic field generated by the coil. The disc turns the pulley since they're connected by the three leaf springs.

When power is removed from the coil, the three leaf springs pull the disc back toward the pulley. The outer part of the bottom side of the disc rubs on the stationary part of the brake. Since these surfaces wear some because of the rubbing, the position of the stationary part can be adjusted with the three nuts. Setting the air gap to 0.012 ensures the three leaf springs will hold the disc against the stationary part of the brake with enough force to stop the blade.

 
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07-17-08, 05:30 PM   #7  
mmmmmm


so the gap is where now??So when the coil is energized, the
gap is "closed"????

So adjusting it closer would do what when disengaged?

I am not trying to fight, but trying to understand you..

When the coil is energized, the coil/gap pulls together,
and if the gap is too great from wear, then problems
can occur......

If I am looking at this device incorrectly, please let me know.

I have been wrong a lot of times, so I can handle it.....


Fish

 
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07-18-08, 04:35 AM   #8  
The air gap is between the rotor and disc, and it's closed when the coil is energized. A smaller gap actually does make it easier for the clutch to engage.

However, at the normal 12+ volts, the magnetic field generated by the coil is so strong that it doesn't matter whether the gap is 0.012" or 0.060".

I've got an electric PTO clutch on the winch I recently built. Since it's so convenient, I did a little testing. I measured the air gap between the rotor and disc. It's 0.035".

Using an adjustable DC power supply, I found it would engage reliably at just seven volts, and I couldn't get it to slip or come apart using both hands. After it was engaged, I started lowering the voltage. At four volts, I could make it slip and come apart. At three volts, it released by itself.

 
Fisher40037's Avatar
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07-18-08, 05:34 AM   #9  
I have never really done any testing on one, but when I have
had mowers with this intermttant problem, an adjustment
often cured the problem.

Adjusting is also free and easy, so I would sure try it.

Isolating electrical problems is never any fun, so hopefully we
are helping the original poster......

Fish


Last edited by Fisher40037; 07-18-08 at 05:35 AM. Reason: spelling
 
rogerflies's Avatar
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07-18-08, 09:05 AM   #10  
I sure hope wmarlowe gets back on to tell us what he does that fixes the problem.

 
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09-17-12, 12:10 PM   #11  
A little Late? Maybe a Help To Others - Repalce Clutch - Fix Smoking Issue

I also had the same issue with my Simplicity Coronet. The clutch would work for a while and then disengage. I also had issues like hard starting and the battery kept discharging. I started with simple, relatively less expensive things like: new battery, replacing the solenoid, replacing the PTO switch and checking the other switches and wiring connections. Finally, the only thing left was the electric clutch.

I ordered a replacement on-lien and installed it myself. The mower has been running beautify ever since. Here are the replacement steps I followed:

-
Removed Mower Deck


-
Disconnrct Battery


-
Raised rear-end of mower so I could crawl underneath (lifter rear wheels on to automotive ramps that were on cinder-blocks.


-
Disconnected wires that go to the clutch (there is a connector on the top side near the front of the engine. Mine also had a connection right at the clutch)


-
Moved Torsion/stabilizer bar out of the way: Two bolts attached brackets that hold the bar in place on each side of the mower. I removed the front two bolts and loosened the bak two bold, allowing me to slide the bar backwards our form underneath of the clutch/pulley


-
Used an electric impact wrench to remove the bolt that (runs through the center of the clutch with pulley) bolts the clutch and pulley to the drive shaft

Remove the clutch by sliding it off the drive shaft. The impact wrench allows you to remove the bolt. Otherwise the shaft just turns.


-
Slide the new clutch back on the drive-shaft. There will be a short metal prong sticking down from the rear deck of the mower. There is a v or u shaped notch in the top/side housing of the clutch (part of the clutch) that should fit around this piece of metal when the clutch is in place. It prevents the clutch from rotating when in use.


-
Re-install the bolt that you took out.


-
Return the stabilizer bar to its original position and install the bolts for that bracket


-
Connect the wires: On my replacement clutch, the power wires with connected directly to the clutch (no connector) so I removed the original wiring connector that originally went to the clutch. My original connector had a diode across the two wires to prevent voltage surges. I re-used this by soldering it between the new connector. (I have read that this is not necessary and the polarity of the connections does not matter � but I did this anyway)


-
Connect the battery


-
Lower the mower and re-connect the mower deck


-
Start and check the installation.


Problems: When I first tried this, I did not place the notch in the clutch housing over the little metal stud. This caused the clutch to rotate, which allowed the wiring to rub against the pulley and drive belt�creating a lot of plastic/electrical smelling smoke. Luckily I stopped the engine after about 60 seconds so no damage was done.) Making sure the wiring was out of the way and that the drive belt was correctly positioned on the inside of the two metal guides fixed the smoking problem.

 
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