Mcculloch Chainsaw Eager Beaver Ii Ignition Coil

Bill W. said:
I think that while fixing this chainsaw you had someone very special looking over your shoulder.
That provides enough inspiration to overcome most any situation. Nice job... Bill
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Bill I must admit it was a loooooong shot to find a coil that with minor mods did the job.
I think my father would feel less guilty now and would be very proud of his son...
Petros
 
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petcnc said:
20 years ago my father bought a McCulloch Eager Beaver II chainsaw to use it for branch cutting to the trees at a distance from home where electricity was unavailable.

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He used the chainsaw the first season and had it in the store room for the next couple of years. When he tried to cut some thick branches three years later he could not start the engine. As the guarantee had already expired, instead of going to the dealer for repair he gave it to an “expert” friend of a friend to fix it. In the mean time he got ill and passed away within the next 6 months, so the chainsaw remained with the “expert”.

A year later my mother tried to find the chainsaw and the “expert” gave her an Eager Beaver II in a very poor condition, saying that it was beyond repair. I believe that chainsaw wasn’t my father’s chainsaw, but as there was no receipt I cannot prove anything. My mother stored it in a box and forgot about it.

Last week I found it consigned in my mother’s store room and took it to have a go with it.

I put some fresh gasoline, I pulled the rope several times, there is compression but no spark. When I researched for problems I discovered that the weak part of the chainsaws are coils that generate the spark.

The particular Eager Beaver II has a simple coil that is not working.

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A search at ebay revealed that the particular coil is not available new anymore, it is hard to find and it is very expensive ($60 for a used coil).

I had to either forget all about fixing the saw or look for an alternative solution.

My first thought was to substitute it with another one from another maker. Unfortunately, every chainsaw maker designs his own coil! Some of them fit other models but none fits mine.

I noticed that coils consist of two separate parts: A laminate iron core and some windings encapsulated in a plastic container.

Most of the coils have similar containers but different laminated cores.

Solution is simple If I find a similar container I could change the core and have a brand new coil!!!!

I looked for a coil that has the same number of laminates with the original one.

It was easy to find it. Made for Husqvarna saws at a ridiculous cost (7.5$ including postage from Hong Kong!

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I ordered it thinking that if it does not work I would have lost the equivalent cost of a six pack of beers!

Coil arrived and it looks promising.

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I first removed the laminate core from the original part

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Then, carefully, I removed the core from the new coil

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A comparison of the two revealed that although they have the same number of laminates (i.e. the same thickness) they have minor differences to other dimensions so I must do some modifications to fit the old one to the new container.

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First the part of the laminate that goes in the center of the container from 7.5mm had to be made 7mm. An easy work for my mill.

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Next the container needed to be1mm thinner for the external leg of the laminate. Another easy job for the mill

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Next, as the old laminate core is 1mm shorter, the container needed to be 1mm lower for a perfect fit.

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Needless to say that During all this machining there was no wiring or electronics exposed so no harm done to the electronics.

So the old laminate iron core fits perfectly to the new coil

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And there is my new part according to original specs (in comparison to the original)

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It fits perfectly on the motor.

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And, most important! it gives spark when I rotate the engine.

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It remains to fix the carburetor and Its done!!!


Thanks for reading


Petros
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Petros,
I found your post while searching for a coil for a similar saw. Your solution seems very good. The coil on my saw appears to be identical. I know this thread is rather old, but could you tell me if your work was successful? If it was good, I would be interested in knowing what model or part number of Husqvarna coil you used as a the replacement part, if it is possible. I might like to try making one myself.

Thank you,
Dan
 
This thread demonstrates why I scrapped out so many of these and other small engine powered tools when I ran my repair business. I would often have to explain to customers why I couldn't fix their tool for less than it cost to purchase a new one, and why doing so wouldn't be ethical for my business.

So, if you (ddc5) want to embark on this repair I believe you now have information to start with. Hopefully you already have a vertical mill and whatever other equipment you will need to do the job. I can say without hesitation that picking up a replacement tool (new or working used) will definitely be quicker and/or cost less than doing the repair illustrated above.

I did occasionally have customers like the OP for whom the tool in question was a physical link with a lost relative and for whom repairing the tool, outboard motor, ice auger, etc. was more about that connection than having the item to do a particular job. For those customers I was always willing to provide advice and parts but I had to tell them that doing the repair was "their project'.

Cheers,

John
 
Oh, I understand your point, it is cost / benefit tradeoff. I most certainly can buy a new saw if necessary. It just always bothers me to throw away perfectly good mechanical devices because some relatively small part is no longer made. And, as manufacturers integrate mechanical with solid state, it gets even more difficult. I appreciate the innovative solution here and it looks like something that I can do with tools I have access to. Many times the old pieces of equipment are worth saving because they actually are more rugged than the cost / weight reduced new tools. For perspective, I say that as a recently retired automotive engineer with a little more time to do these things. In some of my increased available time, I have some old car restoration projects. Currently, I have a 1985 Camaro IROC-Z "barn find" that has been parked for over 25 years. There is much satisfaction for me in putting these things back together again and making them run.
 
Petros: I have that exact saw, still working fortunately. Would you mind giving a link to the vendor of the Husky coil?
Just in case I need to do a similar repair sometime
Mark
ps If I'm not mistaken the timing is set by breaker points so your repair would not change it
 
markba633csi said:
ps If I'm not mistaken the timing is set by breaker points so your repair would not change it
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No points in these it's an electronic ignition. Timing depends on the coils position to the flywheel magnets.
Small timing change avalable by increasing/decreasing the gap to the flywheel.
 
ddc5 said:
Oh, I understand your point, it is cost / benefit tradeoff. I most certainly can buy a new saw if necessary. It just always bothers me to throw away perfectly good mechanical devices because some relatively small part is no longer made. And, as manufacturers integrate mechanical with solid state, it gets even more difficult. I appreciate the innovative solution here and it looks like something that I can do with tools I have access to. Many times the old pieces of equipment are worth saving because they actually are more rugged than the cost / weight reduced new tools. For perspective, I say that as a recently retired automotive engineer with a little more time to do these things. In some of my increased available time, I have some old car restoration projects. Currently, I have a 1985 Camaro IROC-Z "barn find" that has been parked for over 25 years. There is much satisfaction for me in putting these things back together again and making them run.
Click to expand...
I get what you're saying, and the sentiment behind it. If you have the time to put into this saw, and wouldn't rather be working on the IROC then go for it. Just realize you're not talking about a Sthil here or even an older Mac, these were throw away saws when they were built.

My experience comes from working on at least a dozen identical units. My process was simple, check for spark, check compression, check for running with starting fluid. If it failed any one of those tests it would get yellow tagged and the customer notified. I had to be ruthless like that since people would bring me stuff like this all summer long and expect to get a "practically brand new" good running item for $20 and a handshake. I couldn't waste my technicians time on things that weren't worth the cost to fix them, margins were already too tight.

That's where the "your project" part came in. I know guys like to tinker and it's not up to me to tell anyone what's worthwhile and what isn't. I was in business back then and being in a small town I thought it better to send work away rather than tick off my customers with a bill that was more than the tool was worth.

BTW, I've been switching my gardening gear over to battery powered for the past few years and I've never been happier.


Cheers,

John
 
Oh, one other thing to look out for on two-strokes. You can have a brand new carb, working ignition and plenty of compression and still not be running. That's because two-strokes rely on having a good seal at the crankcase to draw a fresh charge into the engine through the carb. If either side crank seal is leaking it won't ever run, or run right. To test for this you have to block off the intake and exhaust and pressure test the whole unit, also something that's more work than most small pieces of equipment warrant.

Cheers,

John
 
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