Toro 724 - No spark?

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  #1  
Old 09-25-07, 06:53 PM
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Toro 724 - No spark?

I own a 1978 Toro 724 with engine 38050. I've never had an easy time starting the engine but have worked on the engine and carb trying to get the machine running with some reliability. I changed the points and condenser; properly gapped it and cleaned the carb. I had it running just last week and it ran well. Now I can't start it. Could it be my magneto? I checked the wiring and I know it has a number of safety switches; all wiring looks ok but is there a way to bypass all these safety switches just to see if I am getting a spark? Sorry to hit you up with so much at once but my back is killing me and I really want to get this running before the weather changes.

Thanks for any help.
 
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Old 09-25-07, 06:59 PM
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Have you checked to see if you're getting spark? Have a look first, before doing other stuff that might not be necessary.
 
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Old 09-26-07, 01:57 AM
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Just to see if your getting spark you can jump it off from the starter moter.And see what it needs from there.

BUT MAKE SURE THAT IT'S OUT OF GEAR FIRST
 
  #4  
Old 09-26-07, 04:38 AM
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Toro 724 spark

Hi Guys,

I do not have a starter and I have tried a few different ways to see if I do have spark but it has not been easy because I do not have any help. I tried pulling the wire off and inserting a screwdriver and placing it close to one of the top bolts (unfortunately everything is painted so I'm not sure if I'm actually placing it near ground). I also tried pulling the spark plug out and taping it close to a grounded area (about 1/8 - 1/4") and have not seen any type of arching. I don't see anything. I did read from a few different sources that rust inside the flywheel could cause a poor spark and I do have a film of rust on the inside of the flywheel. I also noticed some minor corrosion and rust on the magneto contact. I'm assuming that the magneto is the coil and was planning to lightly brush off the contact with a wire brush. I cannot say for sure that I'm not getting any spark and I know that it could possibly be the carb but even if it is the carb shouldn't I get something when I spray starting fluid directly into the carb? I tried that a few times and nothing.

Frank
 
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Old 09-26-07, 09:40 AM
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A model number would help. It is located on the rear frame of the unit and the first two numbers of the serial. Some of these units have remote throttles and key switches both of which if not in the correct position will not allow you to have spark. After you post the numbers of the Toro, we can tell if you need to disconnect anything to check for spark. Also, it is easier to check for spark with the plug removed.
 
  #6  
Old 09-26-07, 04:34 PM
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Toro 724

Hi,

The model number on the tag is 38050 and the serial number is 8006465.

Thanks,
 
  #7  
Old 09-26-07, 06:25 PM
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Remove the spark plug, let it touch a metal part of the engine, and pull the rope while watching the plug at the electrode. It may be a small blue spark that is hard to see in the sun, and you might have a hard time seeing it while pulling the rope at the same time.

Spraying starting fluid in the carb will usually get a pop or something if it's firing and the internal engine components are functioning as they should.

I have never had rust on the flywheel or coil cause a no-spark condition to my knowledge. I've heard of it from other folks, but in the countless mowers I've worked on, I haven't run into this as a problem. I'm not convinced a rusty flywheel can cause no-spark.
 
  #8  
Old 09-27-07, 03:01 PM
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this unit has a key switch and two micro switches that can effect the spark. first disconnect the wire at the junction at the lower engine below the heater box. Next set the throttle at full throttle. with the spark plug removed, pull the engine over with the plug wire near the cylinder head. If you do not have spark, this unit still has breaker points. You will have to remove the flywheel to get to the points and condensor to replace. good luck
 
  #9  
Old 09-27-07, 05:53 PM
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Toro 724

Hi Cheese,

I removed the plug and tried as you instructed; pulled the cord to check for any spark but nothing. I put the plug back in also sprayed starting fluid into the carb but again nothing.

Hi Camino Kid,

I've had the flywheel off and replaced the points and condenser a few weeks ago. I gapped the points and put everything back together and it ran well. I shut it down after about 45 minutes while making carb adjustments and have not been ablt to get it to kick over since.

I once again removed the flywheel and rechecked the gap and all wires and connections and everything looks good. I checked the magnets and both are aligned and seem strong. I also checked the 2 mico switches and both seem to be functioning (I used a meter to check for continuity). The key switch is old but does seem to be working but just in case I jumped the switch. I put the flywheel back on; put the plug back in (new plug) and sprayed starting fluid inside the carb but once again nothing.

I'm assuming that the condenser is grounded and this condenser has a tab on the side that I have sitting on what I think is part of the magneto. It did run so I'm guessing that it should be ok.

I will try to disconnect the wire below the junction box.

Does anyone know if there is a way to check the magneto and spark plug wire? If it is the magneto how tough is it to change?

Thanks to all.
 
  #10  
Old 09-27-07, 06:59 PM
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Ignore the part that says outboard motor lol. Here is how to check the magnito;
http://assets.fluke.com/appnotes/ele...r/B0271b_u.pdf

Have a good one. Geo
 
  #11  
Old 09-28-07, 06:05 AM
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With the wires disconnected at the junction below the heater box, check your wires that lead back to the point box and condensor wire for grounding or rub through. You may want to look at the points to make sure that you have not fouled them with oil, etc. or they are burnt, (bad condensor). With the spark plug removed, I hold the plug wire and rock the flywheel through several cycles to feel for a slight pulse before tightening the flywheel down. If you feel a pulse, then you should have spark.

If you have a volt/ohm meter you can test the coil but very seldom do you find a failure there, mostly mouse nests that have chewed the wires. The lead from the points when disconnected for the coil to ground will have some resistance readings and the same wire to the end of the plug wire will have a higher ohm reading. Then the coil is okay. DO NOT REMOVE THE MAG ASSEMBLY as it is timed to the piston. You will need special tools to properly time. The coil can be replaced by sliding it off point box assembly with some effort if you need to replace it.

It sounds to me like a wire has grounded itself due to a rub or from the heat melted through the insulation. Watch the point box cover for contact with these wires. I have seen pinched wires here and the condensor wire routed wrong and grounding out.
 
  #12  
Old 09-28-07, 02:39 PM
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You speak of a "magneto" and what I think you mean is the ignition coil. If you determine you have a defective ignition coil you do not (and don't want unless you know how to time the magneto) have to remove the magneto (stator) assembly. The coil can be replaced without having to remove the stator.
 
  #13  
Old 09-28-07, 07:27 PM
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Toro 724

I checked the magneto and the numbers were within the proper range.

I pulled the flywheel off again and checked everything out. I did find a wire that was close to beiing ground or was grounded and repositioned.

I now have spark!!!! It was a bright white spark.

Thanks to all that have helped.

You guys are great!

Frank
 
  #14  
Old 09-29-07, 12:27 AM
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Good news! Thanks for the update!
 
  #15  
Old 10-04-07, 04:20 AM
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Toro 724

Hi Guys,

Unfortunately I'm back again.

I had the Toro running and it ran better than ever before.
I let it run almost an hour at varied speeds and when I shut it down I turned off the key and closed the gas valve shutoff.
I decided to run it again yesterday to make some fine adjustments and just let it run again but once again no spark.
I jumped the key switch and retested the micro switches and from what I could tell they are functioning properly. I retested the coil wire and moved it around with the meter attached and it seems fine. I think that I'm going to pull off the flywheel again but before I do I want to be sure that the wiring for the micro switches and key switch are ok. Does anyone know that if I disconnect the ground wire block (under the carburetor area) would that disengage all of the safety shutoffs? I want to be sure that it's not one of the wires on the outside of the machine grounding itself that I just haven't been able to find.

Thanks for any input.
 
  #16  
Old 10-04-07, 11:45 PM
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Yes, disconnecting the wires at the junction on the throttle control near the carburetor area will isolate the engine from the kill circuits on the mower. Disconnect these and check for spark. If you have spark with them disconnected, but not with them connected, then the problem is with the mower electrical system. If you have no spark either way, I suggest replacing the coil with a new one. A new coil will be solid state, not requiring the points and condenser. It is much more reliable, accurate, and easy to use. You can clip the wire to the points and just leave them under the flywheel.

One thing you might check before getting too involved is the flywheel key...in case you didn't get the flywheel nut tight enough. You didn't grease or put oil on the contact area between the flywheel and crankshaft, right? (do not)
 
  #17  
Old 10-05-07, 09:37 PM
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Cheese, this engine does not have a solid state setup for it, unless you install an Atom or other brand chip.

Make sure you have the throttle at high speed as there is a ground switch on the linkage on some of these engines. Disconnectiing the block under the carb heat housing will eliminate the micro switches on the handle bar. If you do not have spark after insuring the throttle is on high and the handle bar switches are disconnected, there must be a wire to the points or coil that is grounding out. Look closely and Good Luck.
 
  #18  
Old 10-05-07, 11:30 PM
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Ah, for some reason I was thinking this had an 11hp briggs. I could've sworn it was...I guess I was thinking of another thread. Thanks for catching my slip!
 
  #19  
Old 10-06-07, 02:53 AM
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Just to be sure you isolate the igntion system, tell me, along with the key kill, can you also shut the engine down by moving the throttle control to a kill position? In other words, does the throttle have an integral shut down in addition to the key switch?
 
  #20  
Old 10-06-07, 05:23 PM
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Toro 724

Hi Guys,

Thanks for all the imputs:

Hi Cheese,

I did realize that I could not convert to a solid state coil when I couldn't find one that cross referenced with my coil part number. My game plan was to remove my existing coil and check for any exposed wires or external damage to the coil. I haven't had a chance to do anything yet but will try tomorrow. Thanks,

Hi Camino Kid,

I did have the throttle on high when cranking and did disconnect the kill switch wiring but still no spark. I also sprayed the wire with WD40 to dry out any moisture (it's been humid here in the Norteast this past week). I will remove the flywheel and give it a real close check for anything that I've missed. Thanks,

Hi puey61,

Yes this Toro has 2 microswitches along with the key kill switch; one for the throttle (when moved out of the N position and another for the rakes when I engage the gearbox. To be honest I have the hand grip (that needs to be un-grounded when I engage the rakes or shift out of N) taped up at this time. Thanks,

I'll update you guys when I open her up again.
 
  #21  
Old 10-08-07, 05:57 PM
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Smile Toro 724

Hi Guys,

I pulled off the flywheel and inspected the two coil wires along with the sparkplug wire. I think I found the problem!!
The wire that winds back under the coil and ties to the the shutoff safety switches was very tight (the routing could have been better). I carefully worked it loose and moved it to where I could see the entire wire and found some slightly damaged insulation. I repositioned the wire and tested for spark and there it was. This was with the two microswitches and key switch connected. It rained today so this was another good test and once again spark. I plan to insulate the damaged insulation along with most of the wire with liquid brush on electrical tape. I have considered changing the wire but will save that as a last option.

Thanks to all for your help.
 
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