Hi first post and need some help please

Snowthrower 24"
Problem: It has no spark

Model: 313-600A I think; no nameplate just Snow Flite 6/24, orange. Mine looks just like this
Engine: HS50 67160b ser 7247b


This was in storage for 10 years, ran when put-away
It turned over and had spark 2 weeks ago before I:

downloaded MTD 313-600 manual 770-2479.pdf
downloaded Tecumseh manual: Technician's Handbook #692509

cleaned out spider webs etc, sprayed throttle cable with lube
oil changed 5w30
removed carb looks like a 632107, series one carb;
carb kit 31840 installed set float level, set main and low speed nominally at 1.5 and 1 turn open
replaced old fuel lines, fresh gas
teaspoon of oil into cylinder, new spark plug J17LM (same as originally in it)
I have "thumb test" pressure at spark plug

installed "newish" pull starter, that turns engine over
120v AC starter engages and turns engine (but will cease functioning after a few attempts.. )I did have to grease the bendix gear to have it engage/disengage properly

I did have the shroud off; other than that nothing else touched, didn't monkey around under flywheel or with plug wire

reassembled, now no spark ... with new or old plug
gear shift is in neutral and wheels free wheel

Is there a neutral sensor that is killing my spark?? LOW OIL SHUTDOWN SWITCH ?where do I proceed from here?

Help is welcomed.
Paul

 

Go to the electrical connection that kills it and disconnect the wire at that control and recheck for spark with good plug, well grounded. If you had the spark before and haven't ran the engine, there's a good chance it still around.

 

Hi marbobj:
Disconnected the electrical connection wire. (Tecumseh 610973 Terminal Assy.) from frame. Still no spark (used 3,rd good plug).
I do have continuity from this wire to the frame. I may have pinched wire during re-assembly? I will pull shroud off and check.

This should now be open circuit, to run right?

 

Right - the wire should not be grounded = continuity to, say, the engine casing. The kill grounds the circuit to the ignition module (coil).

To make sure we're talking about the same thing, though, a wire comes into the kill control (usually on the throttle - stop position) or it can be on a separate switch like an ignition, keyed switch. The wire coming into the kill switch is coming from the ignition module. The switch grounds that circuit to the frame or engine casing, etc..

 

Hi \
Yes we are on the same page "a wire comes into the kill control (usually on the throttle - stop position)" has been disconnected from throttle body, it now goes solely into the ignition module (under the flywheel )
Removed shroud and wire apears to have good insulation on it . Pushed it back 1/2 " into flywheel cavity , to ensure wire was not shorting out on casing. Still have continuity to ground on the wire.
Key switch is not in circuit, disappeared long ago... Real plainjane ...

 

With that, disconnect the wire from the module and check for spark at grounded plug. If you can't get anything your module (coil) could be bad. The gap between the module and the flywheel should be .010 or the thickness of a business card. If your gap is correct and the the module hasn't been inverted (some can be and not work), the ignition module is likely bad.

Do you know how old this thrower is? How many wires are coming off the coil? Pre-'86 engines have points/condensers. That puts a new twist on everything in the ignition.

 

From the serial date code I think it may be a 1977 (doubt it is a 1987, can't see a flywheel safety brake. Plus when I got it in mid 90's it looked OLD then). So it should have points and a condenser. Could I have sheared the flywheel key when trying to start it (I did try before the lube went in the cylinder, oops)?

Only that one wire and the spark plug wire comes out from behind the flywheel. Will try to scrounge a puller up tomorrow so I can check these things out

 

If it was point/condenser it would have the two wires - one to points and one to kill, but the other wire would be behind the flywheel.

If you have only one wire plus the high tension lead from the coil, it would be a module (CDI job). You might pull it off and clean the mounting for it to make sure it has a good ground for the module, but if that's OK, and the gap is right (.010), no spark leans towards a new module. They run around $35.00 to $50 depending on the engine and the source.

If you find there are two wires coming from the coil, the problem is likely in the points or condenser = a lot cheaper to fix.

 

Hi marbobj

OK, a 3'rd arm came by today and I now have the Flywheel off. (2 light taps and it popped off embarrassingly easily)

Points and condenser inside. Very RUSTY.
I will replace with new
Flywheel key not sheared or bent
I will replace with new.

I'm reading up on how to install new parts now
Any insight would be welcomed ie. any special tools needed or helpful hints

Any checks on the coil, I can do today? Before I go to town for parts tomorrow?
Thanks
Paul

 

Does anyone know if I can replace the points/condenser without removing stator plate?
I have no dial indicator. and no way to reset timing. I have not removed anything yet.
Or can I scribe it and replace it in the same position later?
Would this work??

 

Ok have points p/n 30547a
and condenser p/n 30548B (It is not as tall as the rusty one installed).

• Installed condenser
• (leaving points alone for now, they open and shut and are at .02in)
• lightly sanded rust off armature edges, facing the flywheel magnets, while still in place, still no spark
• coil has 2 wires from it and the spark plug wire

Does this just slide up and off square post? I have released some lock-down retaining clip on the edge of the coil but it seems pretty solidly attached. Don't want to bust anything. Is there anything else to release?

 

Did you clean the points? If you have a finger nail file handy or better yet a point file, clean them up and recheck the point gap. If they have any corrosion or oil film on them it will cause a no spark.

Just re-reading your post on the coil. No the coil does not come off that square post. You take the coil off as an assembly with the u shaped jobby it's mounted on. That whole thing is a unit. You'll see the two mounting screws that hold it on.

Wait a minute, back up, is your coil inside the flywheel or on the outside?

 

Coil is inside the fywheel looks like this Tecumseh 30560A

 

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Here is pic of the setup.
Cleaned the points with some cardboard sprayed with carb cleaner.

 

The parts of that ignition system are the points (to create a ground/break ground for the coil saturation/discharge), the condenser to bleed off excess voltage, the coil and plug. That stator plate is used to set the timing.

The coil will pull off the square post you have in the picture, but I can't tell you about any retainers that are on it. I've only seen a couple like it.

The considerations in trouble shooting are: the points opening and closing, the point gap, the continuity across the points when closed, the grounding of the fixed point contact, a good condenser and the condition of the coil. The coil can be isolated by disconnecting the wire going to the kill and the wire going to the points has to be left connected.

If you have the points covered, it's down to the coil being bad, although the ratio of points to coil as being at fault is quite high.

 

Hi
Ok I pulled the wires off from the coil (still can't figure out how to remove this 3 decade+ coil, local repair shop closed)( there is supposed to be a coil wedge in there?? Part number 18) any ideas??
[item 17 p/n 31311 Clip, Coil locking]
[item 18 p/n 29629 Spring, Coil wedge]

Without any wires to item#7 [Tab, Ground terminal] the points make and break electrical contact: closed grounded to frame; open no continuity to frame ground

But when long wire from coil to attached to this lug everything is grounded.. (The short coil wire is grounded at the condenser canister) Doesn't matter if points are open or closed

So is this my problem: bad coil?. Or is this correct and reassemble again and try it? raining again.

If I could get the old one off without removing the stator plate I would I'd just fork over the cash for a new coil. Like you said, process of elimination, and there ain't that many parts
Thanks
Paul

 

The coil shouldn't be grounded through the stator plate = with all three wires disconnected (two plus the plug wire) the coil wires would not have a continuity to ground.

As far as removing the stator plate, don't worry about it if the screws come out easily. Just take it off, take off the coil, and reinstall to the screw marks. It will be pretty evident where they were. When you have the coil off, I would sand the rust off the stator posts. Make sure you don't sand the screw imprints clean.

Also check any of the connections like where the coil wire goes through that little plastic job in the point casing. That has to insulate everything from the coil to the points. Sometimes that little piece of plastic breaks and the circuit makes ground.

 

Hi Marbobj

Its running!!

Did what you said and removed stator. Scribed the location first
Put the new points in. and set to ~.020
Attached new condenser
Really scrubbed off rust on armature Could not get old coil off, so left it alone
Reassembled and had spark turning the flywheel by hand.
Bolted it all up and primed the spark plug hole.
Fired right up
Standard setting on idle and high speed are real close with 1 and 1.5 turns out.
It idles and runs at top speed with very little 'hunting", and shuts off too. and restarts easily

[BTW the kill wire still shows continuity to ground always except when the points open. sort of seems ass backwards to me but guess that normal. (also for reference ~8 k oms from spark plug to ground and ~ 3 ohms across the little coil wires were my reading for my working coil).]

Thanks for the help
Paul
ps auger turns and it has forward and reverse gears working

 

Not sure about the continuity you're describing, but from experience, I've learned not to question something that's working.

Take care.