Removing flywheel to replace key

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  #1  
Old 09-03-13, 04:45 PM
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Removing flywheel to replace key

New to this forum. I've searched and read several threads about this but I need help for my specific problem.

Item:

Craftsman Mid-Engine Electric Start 30" Mower/Mulcher Hydrostatic Drive model 5363.270320 (Riding mower)

Engine: Briggs & Stratton model 21B807-3026-E1

Problem: Flywheel turns but engine won't start. Started acting up in beginning of season with intermittent stalling. Now no longer stats at all.

Having read previous posts I'm almost convinced the flywheel key is sheared
(item 24 p/n 222698s).

I've got gas in the carb and the fuel solenoid is operational. I'm quite sure I'm getting spark.

My problem is getting the flywheel off. The plastic fan on top of the flywheel is held on with a bolt (not a nut). How do I prevent the fly wheel from rotating? I noticed an approximately 3/8" dia hole in the side of geared flywheel that is exposed as if a steel rod can be used to insert and hold as a counter pry against the socket wrench. But, I have no place to wedge the rod against.
Is this is what that hole is for? Can I get a helper to hold the bar while I try to loosen the bolt? Or is that hole just a machined hole to balance the flywheel?
Since I'm not absolutely convinced that the key is sheared I'm reluctant to buy special tools that I'll never used again.
 
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  #2  
Old 09-03-13, 06:03 PM
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Geo came up with something most of us tell members to use for keeping the flywheel from turning when taking the flywheel nut/bolt out. You take out the spark plug and stuff a nylon rope down the plug hole when the piston is in the down position. Then run the piston up against the rope, take out the nut or bolt, then pull out the rope,

Thanks Geo.......Salute
 
  #3  
Old 09-03-13, 06:05 PM
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Have you removed the spark plug and pulled the starter rope with a finger over the spark plug hole? You should feel the suck on intake and pressure on compression strokes if the flywheel is turning the engine.
 
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Old 09-03-13, 06:28 PM
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Thanks marbobj but I can't take credit for the creation of the rope method for locking the engine, however I do take credit for promoting it's use heavily, I cant remember how many fins I have broken from the flywheels before I came across the method. Have a good one. Geo
 
  #5  
Old 09-03-13, 06:33 PM
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I started using it after you suggested it. You had another little ditty on wire connectors to turn carb mixture screws. No wonder Missouri is leading the nation.
 
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Old 09-05-13, 01:01 PM
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Due to the location I'm unable to reach my finger or thumb over the SP hole. Besides, its a key start not a pull start. However, I am able to hear a swishing noise as I turn turn the flywheel via the wrench without the SP installed.
 
  #7  
Old 09-05-13, 03:01 PM
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Even if the flywheel key is sheared the flywheel will usually still turn the engine over. And if the coil circuitry is good you will still have spark. but if the key is sheared the spark will occur at the wrong time on the the revolution of the crank and it won't start.

The most common cause of the sheared key is the blade hitting something solid. The the key shears to avoid damage to the crank.
 
  #8  
Old 09-05-13, 05:10 PM
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marbobj, thanks for the confirmation about that. I had my doubts.

In my first post I said I was confident I had spark. Well I decided to actually do a physical check. DUH! It looks like I don't. So now my attention is turning to electrical. Any suggestions as to what to look at first? Also does the film of surface rust on the flywheel and magneto make a big difference? Should I use emery paper to clean it off? In addition I used a feeler gauge to measure the gap between the two (.010). Is that critical?
 
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Old 09-05-13, 05:54 PM
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Knock the thick stuff off - wire brush or emery cloth. A good thing to use to set the coil (module) against the flywheel is a business card (or about that thick). Rotate the magnets under the coil, stick the card in for a spacer, release the bolts on the coil, it'll draw down on the card, tight the bolts and rotate the flywheel away and pull out the card.

While you're in there, disconnect the wire coming out of the coil from the wiring harness and check for spark. If none then, the coil is likely bad. If a spark with it disconnected and no spark with it plugged in, then a wiring harness or safety switch is grounding it.
 
  #10  
Old 09-06-13, 08:06 AM
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I'm getting confused. Here is a pic of the magneto. Is that what you're referring to as the coil?



The thin black wire just to the right and below the thick SP wire (circled in yellow), is that the one you refer to for checking spark? It clips on the underside of magneto then goes to a connector (I assume) to the solenoid that the battery pos. term is connected.
 
  #11  
Old 09-06-13, 08:13 AM
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That's the one. Just follow it up the first connector you can split it at. Then mount the coil in place (card between it and the flywheel). Then check for spark with a grounded plug. Usually it's easier to see in a dark garage. It should be more of a blue than yellow.

The small wire is a kill wire, not a positive current feed. The coil with the "U" shaped pickups is a module with a capacitor discharge device (CDI) and a coil (saturated it provides the main spark) The capacitor loads to capacity, then triggers the discharge of the main coil as the magnetic field on the flywheel has passed the pickups. The capacitor essentially replaces the old style point/condenser design. The coil itself pretty much does the same thing it always has.

You disconnect the small wire to isolate the module from any other potential shorts or failed safety switches, which act to ground the system = kills the spark.
 
  #12  
Old 09-06-13, 08:43 AM
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Thanks for the clarification. This seems to be a common item. Local supply house has one in stock for $44.00 plus tax.

Small Engine Suppliers - Your online source for Replacement Small Engines, Tools & Parts

has it for $29.95. Foe the sake of a few days shipping I'll order today and have it next week.

Thanks again.

I'll follow-up on this thread when the new part is installed.
 
  #13  
Old 09-06-13, 08:51 AM
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You said, "The thin black wire just to the right and below the thick SP wire (circled in yellow), is that the one you refer to for checking spark? It clips on the underside of magneto then goes to a connector (I assume) to the solenoid that the battery pos. term is connected."

If you have that wire connected to the positive side of the solenoid, that coil is ruined and the new one will be as soon as you connect it. That wire should never have battery voltage on it.
 
  #14  
Old 09-06-13, 09:15 AM
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No. Never disconnected it from the other end, just from the coil. It in turn goes to a harness that's wrapped in tape. Other wires coming out of that harness go to the solenoid. My confusion came from the manual wiring diagram. It says this wire should be yellow, but its black. But then again the schematic shows this wire making its way to the ignition switch which is yellow on the machine. Which I assume is the kill mechanism as marbobj indicated.
 
  #15  
Old 09-06-13, 10:42 AM
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It can get a little confusing since most of us think in terms of ignition is voltage and we supply voltage to run the engine and cut it off to kill the engine. That system was on some small engines years ago. They were battery/coil/points/condenser. A lot of those engines are still in service.

But most of the small engines now have the self contained ignition modules which are fed by the magnetic field off the flywheel. They don't require a remote power source like the battery. So you stop that engine by grounding the system, either through the ignition switch or with a slide throttle control with a kill position on it.

However the hardware is set up, the function is pretty much the same - it grounds the module to kill the engine.

I take it you got no spark with the kill wire disconnected?
 
  #16  
Old 09-06-13, 11:50 AM
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I'm at a loss.

After seeing the price of shipping, for just few bucks more I bought the coil locally. Installed it, gaped it, still no spark. I borrowed a impact wrench and removed the fly wheel bolt and examined the key. It looks intact.

Should I be testing for spark with or without the kill wire attached? What is the next most likely electrical part to inspect/replace?
 
  #17  
Old 09-06-13, 12:46 PM
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on the old coil you would have disconnected the kill wire, then grounded the plug on the engine fins, then turn the engine over. If no spark, replace the coil.

The condition of the key doesn't affect the spark, only the spark timing.
 
  #18  
Old 09-06-13, 02:01 PM
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OK, I've got a good strong spark. At least that eliminates an electrical problem. (I don't even want to test old coil. Lets just assume it was bad and leave it at that! )

Now, when I removed the fan and and was able to look down into the flywheel shaft I said it looked good, but I did not remove the flywheel itself. I'll need a wheel puller for that. But the part I could see showed no deformation or looseness. I suppose it could've sheared at the lower section and not show any signs at the top. But I have not hit any ground item that might've sheared the key.

So I guess the next area of concern is gas. When I removed the solenoid plunger from the bottom of the carburetor bowl a good portion of gas flowed out and the plunger actuated easily when ignition applied. Now I must tell you that the gas is old, but has been treated with Sta-Bil. And its not so old that is should not ignite. My next step is to remove the carb and see just how gunk'd up it might be?
 
  #19  
Old 09-06-13, 03:21 PM
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I would stick some new gas in it and see if it will start.

When a flywheel key shears it doesn't really grind up anything. See if it will start first and go from there. The key may be OK.
 
  #20  
Old 09-07-13, 08:08 AM
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I squirted some starting fluid into the SP and tried starting. Nothing. I'm going to secure a wheel puller and check the key.
Will report back later.
 
  #21  
Old 09-07-13, 09:28 AM
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I wouldn't do that just yet. There are a lot of reasons for a no start other than the flywheel key.

I would remove all the gas from the tank or shut off the fuel to the carb. Then full choke, half throttle spin it over to get the gas out of the carb. Then no choke, full throttle with the spark plug out spin it over a few times to purge the combustion chamber of vapors.

Then put a teaspoon of gas down the plug hole, put the plug back in it and pull it until it tries to start.

If it does, put the gas back in the tank, and half choke, half throttle, see if it will start for you.
 
  #22  
Old 09-07-13, 01:09 PM
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Here is where I stand at the present moment. I went ahead and removed the flywheel. The key is good. That removes the possibility of that problem.

marbobj, I did as you instructed and turned off the gas supply removed plug and tried to flush out any unused gas. Added a squirt of starter fluid to the SP hole. BTW... My chock and throttle are all the same lever. Can't half chock and half throttle. It's either all chock for starting or full throttle for normal running. I then removed the carburetor, blew out the unit with a gentle air hose. Removed the carb bowl and check the inside. No signs of varnish or debris. Looked very clean. All gaskets in good shape. Re-assembled and retried. The starter turns the engine but not even a sputter or cough. I even by-passed the starter solenoid to jump start the unit. Same results. I doubled checked for spark and its OK.

Just a quick re-cap of symptoms before it stopped starting. At the beginning of the season it ran well. Then occasionally it would begin to die out. If I quickly played with the chock I could keep in running and then it would smooth out for several minutes and all was right. Then perhaps several minutes later or maybe even the next week it would start acting up again. Some days it would run OK for the entire grass cutting session. On the occasions that it did stall out, if I re-oriented the position of the mower by turning it to the opposite direction, it would usually start and run fine. Sometimes I would just wiggle the gas line and it would restart. That's when I replaced the gas filter. Seemed to help at first but then back to the same old problem the following week or maybe two weeks later. Sometimes it would die out as I engaged the blades (putting a load on the engine) but not always. By all appearances, it seemed that it was starving for gas. If put I put it to full chock if it started to stall it would tend to rev up again and run smooth. But not always. The last time it ran was when I drove from the back yard to the garage to work on it. And as it happens that last drive the engine ran smooth. But since then it won't start.
 
  #23  
Old 09-07-13, 03:23 PM
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Yep that sounds like a fuel issue. the first thing we need to do is get it to try to start off a hand feeding through the plug hole. Your setup goes from full throttle right into the choke, then? I follow.. Just get all the gas out of the tank or shut it off, then throw you throttle all the way into full choke. Spin it over to get the fuel out of the carb. Then put the gas down the plug hole and drop the throttle out of the choke position. With spark and compression it should try to start.

I would just use gas to prime it, no starter fluid. That stuff can flood easily.
 
  #24  
Old 09-09-13, 06:24 AM
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WOW!

Went out this morning and tried something. Turned key and it started right up.

The engine runs just fine now. Never had a fuel problem, never had a spark problem, never had a flywheel key problem.

I do however have an electrical problem.

Question me this?

How does the kill wire operate?

When I questioned the spark test earlier on in this thread I said I was not getting spark at the plug. I was advised to disconnect the kill wire. And sure enough I got spark.

All other attempts to start the engine had the kill wire attached. And in testing for spark I had to disconnect the kill wire. So I said to myself "Self, why not try it without the kill wire attached? And what is the difference with grounding out the plug for testing or threading it into the engine block." Tried it and it worked.

Now it starts with the key and shuts off with the key.

So why do I have a kill wire attached to the coil? Should I be using it? If I don't what is the risk? It was on it when I bought the mower and connected when I started having this problem. Do I have a faulty ignition? Or maybe the kill wire insulation might be stripped and shorting out? But it works with out it! Do I just forget about it or not?

BTW... I learned a lot from all the feed back, especially from marbobj. Thanks.

edit...

I traced the kill wire to its source to the first connection point. No stripped insulation. Looks in good condition.
 

Last edited by Norm201; 09-09-13 at 07:40 AM.
  #25  
Old 09-09-13, 09:09 AM
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If I'm on the same page with this:

You had a no start - concerned with a sheared flywheel key.
You checked the old coil with the kill wire disconnected and got no spark.
You replaced the coil and got spark = bad coil/module.

** At this point everything would be OK on the mower except the coil. You fixed the problem by replacing the coil.

If you replaced the coil with the kill wire disconnected and got no spark = the coil you put on was bad or possibly the spark plug wasn't grounded properly.

Now apparently everything is working, where it wasn't before and you have a new coil = fixed the problem.

As for your question: the kill wire works by grounding the ignition system. It also allows a number of safety switches to be plugged into the kill circuit. Those would be switches under the seat (operator present) and blade engagement which usually thread back through the seat switch, depending on the design of the circuit.

This is why you were instructed to disconnect the kill wire from the coil. This isolated the coil from the safety circuit. If the coil checked out good with the kill disconnected, you would likely have had a problem in the ignition switch or the safety switches. The most likely problem that occurs is in the seat switch.
 
  #26  
Old 09-09-13, 09:31 AM
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Weather I had a bad coil from the get go or not is water under the bridge.
With the new coil and kill wire disconnected I got spark, with wire connected, no spark.

There is only one push button style switch that must be closed by sitting on the seat. At this point it no longer works because the kill wire is disconnect. So at this point it appears I have a bad ignition switch.

Now after starting and running I can only turn off the engine by putting it to full chock and turning the key to off position. Only the full chock position will allow engine to be shut down (assume from a flood condition). I would prefer to by pass this safety switch button if possible. My question now is, am I doing any harm to the engine by shutting it down by the chock?
 
  #27  
Old 09-09-13, 11:23 AM
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Killing with the choke would be the only way to kill the engine with the kill wire disconnected. That wire is the only thing that stops the ignition to the engine. Your mower doesn't have an enabling circuit to the ignition, it's self contained at the module. It only has a kill circuit - the kill wire leading to ground. It's not a good idea to have the kill circuit or safety switches disabled, except for testing.

The ignition switch works through the kill circuit of the seat switch. So if the ignition switch is good or bad, it does nothing to control the engine if the seat switch is bad or at least problematic.

The chance of your seat switch being the trouble vs the ignition switch being bad is at least 5 times as great. The ignition switch is used once vs the constant movement of the operator on the seat/seat switch. When a seat switch causes trouble there are two places to check - the connector to the switch and the plunger in the switch.
 
  #28  
Old 09-09-13, 12:44 PM
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I tested the kill switch for continuity. Checks out fine. It's nothing more than a push button that makes or brakes contact. And the switch isn't exactly located under the seat, but under the front of the seat frame that pushes down as you sit on the machine. Since one must be sitting on the seat to keep the engine running the frequency of the key being used is at least as much if not more as the seat switch being depressed (the key switch also has a reverse direction cutting mode that I use often. As a result it gets turned more often than I get on or off the seat.). In fact it's such a nuisance that I can't stop the mower without shutting down the engine every time I need to get off to clear debris, pick-up dog crap, get a drink or talk to a neighbor. That's why I was hoping to defeat the kill switch for the engine. Another thought would be for me to install my own on-off toggle switch inline with the kill wire. Then turn it on to stop the mower.
That way I can still keep the engine running but get off the machine without restarting each time.
But I see that that would not stop the blades from turning unless I deliberately disengage them each time I got off. Not such a good idea I suppose.

But my question still stands...Does stalling the engine via the chock cause and harm? I think not but I'm not sure.

Edit...
Think I just answered my own question. According to the manual they explicitly say do not stall out engine via the chock as it can cause backfiring and possible damage.
 
  #29  
Old 09-09-13, 01:02 PM
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Looking at simply flooding the engine to kill; you're introducing an overly rich mixture to the upper cylinder to stop the engine. The extra gas dilutes the oil on the cylinder wall and could be argued that it will lead to premature wear.

Another problem would be the flooded condition you would be creating for subsequent starts. That could be the biggest headache.

If the seat switch is working well, not with continuity but rather with discontinuity, when depressed, I would just replace the ignition switch if there are no other safety devices on that mower.

Should you decide to install a toggle to accomplish the same thing, it would work to ground the module and kill the engine.
 
  #30  
Old 09-09-13, 07:03 PM
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The kill wire is grounded. Put an ohmmeter on it and trace it back, working the safety switches, wiggling the wire, or whatever it takes until you see the continuity to ground disappear for a moment. When you do, you've found the problem area. The switch at the blade engagement lever has given me trouble on these mowers for what it's worth.
 
  #31  
Old 09-10-13, 11:50 AM
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Last word on this thing.

I did use an ohm meter and did as suggested. Traced every junction and switch. Every thing checks out. However, now without the the kill wire attached the key does in fact turn off the motor without using a chock or flood condition. ??????

Of course the engine, blades and drive will not shut down if I were to get off the unit. Since I don't have kids or pets running around and I'm very safety conscience I'm not disappointed over the fact that I can get off with out the engine shutting down. And I will make sure I disengage the blades.
I decided in the name of time, frustration and money, I'll live with the situation until something occurs to change it.

I even bought another ignition switch thinking it was an intermittent occurrence. Same scenario with a brand new ignition switch.

A great big thanks to all of you for spending your time and patience with me on this. I learned a lot in spite of not getting it fixed perfectly.
 
  #32  
Old 09-15-13, 06:07 AM
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My last post said that was to be the last word on this nightmare. Well, looks like I lied.

Ran the mower for about an hour last week and cut my back yard. No problems what so ever. Started right up, engine ran smooth and it shut down by just turning the key to the off position (remember, I disconnected the kill wire).

Yesterday I started it, pulled out of the shed and ran the mower for about 15 minutes when it started running a bit rough. I chocked it a bit and it smoothed out for a moment, then started dying. Repeated this about three times and then it died completely and will not start again.
 
  #33  
Old 09-15-13, 04:08 PM
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What you had left when you thought you disconnected the kill wire from the module wouldn't allow you to kill the engine with the switch. The only way to kill the engine electronically is through the kill wire and it would have to be connected to the kill/safety circuit. You must have done something else.

If it doesn't start at all now, check for spark again with all the wires just the way you have them.
 
  #34  
Old 09-15-13, 05:30 PM
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Several hours later...it starts, several times throughout the day.???

Kill wire is still disconnected and it still shuts down without a chock condition just by turning the key.

I'm beginning to think the fuel solenoid is not working on a consistent basis. Even though I pulled it out and applied current to it and it plunges up and down, I'm thinking that maybe it stops as it gets heated up. Does this make any sense? When it acts up it does seem as though its starving for fuel. And by turning the key to off position does the plunger default to a closed or open position in the carb bowl? Is that why it seems to be shutting off because its starving for fuel? Although it shuts down within 10 secs of turning the key, it seems as though that it takes a bit longer than if the kill wire would be attached. And if the electronics of the solenoid is defective will that cause the unit not to have spark with the kill wire attached and everything is assembled properly?

I'm grasping at straws here. A new solenoid is $40.00. I hate to keep replacing parts with no results. I already sunk about $75.00 including new coil, plug, ignition switch and gas valve.

 
  #35  
Old 09-15-13, 06:00 PM
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Default for no current to the plunger would be closed.

The only way to ground the coil and kill the spark is through the kill wire coming out of the coil. You've disconnected the small wire leading to the coil right at the coil, and if the engine kills in about ten seconds, then the switch isn't killing the spark, it's shutting off the fuel at the fuel solenoid and the engine kills for lack of fuel and not for lack of spark.
 
  #36  
Old 09-16-13, 07:08 AM
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IF you think that fuel solenoid may be acting up, I would prop that little valve open with something open on one side to let the fuel through and run the mower for a while to test that thing. If that fixes it you know where to go.

That solenoid is to control the backfire after shutoff. It blocks the fuel flow when the ignition switch is shut off.

I don't believe there is a connection with a bad solenoid and a no spark on the module.. at least I can't put one together myself.
 

Last edited by marbobj; 09-16-13 at 07:39 AM.
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