Toro TC 3105 ignition coil

[BrianX128]

I've got one of these toro weed eaters that my dad wanted me to fix up for him as it was his favorite weed eater and it turns out it has no spark. I looked online for an ignition module and there is one on ebay for 70 some dollars and I can't find anything else that looks right anywhere. Here's a picture of that one, the one for the weed eater is in the garage somewhere and I can't find it now.

 

[jp1961]

Hi Brian,

I looked on parts tree.com and the coil is no longer available. Ebay is your only option, unless a local Toro dealer has one sitting on his shelf, or possibly one from a scrap heap at your small engine repair shop.

I'd check the grounding wire to see if it's shorted to ground or sometimes the metal clip that attaches to the spark plug has come off the cable. Try disconnecting the kill wire all together as the kill switch might be bad.

70.00 is a lot of money to put into an older string trimmer.

Regards

Jeff

 

[BrianX128]

So I tried messing with it again, it doesn't have a spark but it is trying as the volt meter shows. I think the most I'm getting is 10v. I looked at the flywheel and it looks like it had been sanded before to "clean" it with a wire wheel or something.

Since it's useless as is and impossible to get parts for I think we're onto "do whatever" stage of fixing. It looks like the gap between the coil and the flywheel is just too big looking at some of my others that work, I think I might drill the holes out in the coil bigger so I can slide it more towards the flywheel and see if that makes the electrical pulses strong enough to generate a spark.

I tried the volt meter in the end of the plug wire and it's the same as where I cut it to see if I had electricity there.

 

[jp1961]

Hi Brian,

The air gap between the coil laminations and the flywheel magnet should be roughly .015". A 3"x5" index card folded in half or a piece of paper folded into 4 layers will get you in the ballpark.

All the coils on the engines I have worked on should adjust from coming in contact with the flywheel out to .015",,,this the original coil?

Regards

Jeff

 

[BrianX128]

I tried getting it so close it might have even rubbed a little bit but it won't make enough juice to make spark. Shows up on the volt meter but that's it. I rigged another coil that doesn't hit at the right times up and it makes perfect spark, so it's just a dead coil at this point. All things considered, the whole thing is likely junk since I can't get a coil for it anymore but at least I tried.

On to the next one.

 

[upupandaway]

the whole thing is likely junk since I can't get a coil for it anymore

I wouldn't toss it. I had some 80's machines - 1 that had a bad cylinder, 1 bad ignition, etc. where sooner or later the part(s) showed up on ebay for $10 and they run today.

you know, I actually had an old old fs80 where i thought the ignition coil was bad. Eventually getting one for cheap, it still didn't run. Eventually i borrowed the flywheel from my another 80 and found the flywheel magnet was the problem. I guess it lost its charge. I had similar symptoms as you - originally some voltage but no spark. Just saying....

Can you take\post more detailed pic of the ignition coil? JC.

 

[bertsmobile1]

A reading on a volt meter means next to nothing.
The coil has a timing chip embedded into it ( replaces points ) and unless it is working the coil can not make a spark.
Also this makes coils unique to a particular engine so it is hard to find an alternative one that works properly.

Big workshops & glass fronted franchise retail agents pretending to be mower shops toss out all of their U/R's unless the owner wants them back.
Small independent shops . particularly if they are run from ahouse or they own the shop will keep U/R's to salvage parts from so that is what you are looking for.
Randys is also worth a try.
HE is AFAIK the only chain saw breaker but he has a fantastic knowledge so will happily tell you that the coil from a xyz55 will fit & work on your engine.
Because Weedeater are a lower end product now days very few people bother with them because it is a loss making venture.

FWIW I inherited about 2 cubic meters of old line trimmers as part of the stock when I took over 6 years ago.
This is now about 10 cubic meters . The high end stuff is broken to fix high end machines . The low end stuff is tagged and when some one need a part they can take the whole unit for free.
I got them for nothing, it is not worth my time to pull them apart & fix a machine that was 2 hours labour to buy new and it makes for excellent customer relations.
Every now & then some local kids get a trailer load of old Ryobi stuff to pull apart & play with, again for free. A lot cheaper than putting adds on local media.