Jonsered 70 E flywheel question

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rlamppa1

rlamppa1

ArboristSite Lurker
Joined
Oct 26, 2016
Messages
27
Location
Minnesota
Hello:

I picked up 70E for $20. It's all intact and looks pretty good other than it has never really been cleaned. The original owner said it ran up until last year. This is my first 70E. I have several 621's. I was going to check for spark and when I pulled the spark plug cap off the whole wire came with it. Then I took the rewind off to see that the plastic flywheel has disintegrated. If am lucky enough to find a flywheel, I have a couple questions. Am I able to just screw a new wire into the coil? Also, the coil doesn't appear to have a pick up on it to set an air gap. Never seen a system like this. The coil is attached to the rewind cover. Looks like a brass or copper nub on the cover lines up with one on the block. Each has a wire going to it. I see no magnets on the flywheel itself. Do I need to just screw an new flywheel fan and it should run. If I replace the plug wire, it looks like it should run, other than I shouldn't run it too long because of a lack of cooling? I see a guy on Ebay is selling 3-D printed flywheel fans. Has anyone tried one? Thanks for all the help.
 
Blackbruin

Blackbruin

ArboristSite Operative
Joined
Apr 2, 2011
Messages
209
Location
Central Pa
Hello:

I picked up 70E for $20. It's all intact and looks pretty good other than it has never really been cleaned. The original owner said it ran up until last year. This is my first 70E. I have several 621's. I was going to check for spark and when I pulled the spark plug cap off the whole wire came with it. Then I took the rewind off to see that the plastic flywheel has disintegrated. If am lucky enough to find a flywheel, I have a couple questions. Am I able to just screw a new wire into the coil? Also, the coil doesn't appear to have a pick up on it to set an air gap. Never seen a system like this. The coil is attached to the rewind cover. Looks like a brass or copper nub on the cover lines up with one on the block. Each has a wire going to it. I see no magnets on the flywheel itself. Do I need to just screw an new flywheel fan and it should run. If I replace the plug wire, it looks like it should run, other than I shouldn't run it too long because of a lack of cooling? I see a guy on Ebay is selling 3-D printed flywheel fans. Has anyone tried one? Thanks for all the help.
That reprinted flywheel is better than oem.
Well worth it.
Sometimes shim the contacts on the starter cover to case. It's all it needs.
 
Cantdog
Joined
Feb 17, 2009
Messages
15,864
Location
Beautiful Rockbound Coast of Maine
I would start by getting fire to the plug...many times the connection from the recoil to the case is faulty....a small washer for a shim as was said will help. Reinstall the plug wire into the coil and make sure the spark plug end has secure contact to the wire as well........you should do all this before you buy a new fan as the SEM module located under/inside the flywheel may have failed. These are pretty hard to come by and expensive if you can find one. If you can get fire to the plug then by all means get a new fan but if you buy the fan then find you have a bad coil or SEM module your investment will go way up before you have a running saw. Or just keep and eye out for a trashed 70E with the parts you need that you can buy cheap....
 
Cantdog
Joined
Feb 17, 2009
Messages
15,864
Location
Beautiful Rockbound Coast of Maine
Thanks for answering all my questions. It is much appreciated.


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Well you're welcome....been dealing with these saws since they were current so I pretty much have a handle on them. The 70E is a favorite of mine having spent years logging with one......but that said they have "soft spots" that are electronic based.....which was not such an issue back when you could get parts. Though they were the first of the modern single ring saws with "electronic" igns" the ign system sucked. That is why the late versions of the 70E lost the plastic fan for an alum one and a cyl mounted coil/pickup and a trigger unit under the carb. The conversion is simple but requires changing the cyl as well as the flywheel......but that too is an option if you can find one in a parts saw.....the 621 Jonsereds and 80 and 90 are actually more durable examples with points igns.
 
rlamppa1

rlamppa1

ArboristSite Lurker
Joined
Oct 26, 2016
Messages
27
Location
Minnesota
I’ll keep you posted if I get fire. I’ll be busy with work the next few weeks to spend too much time on it. For $20 it’s in pretty nice shape. I’ll agree it’s not built like a 621. One quick question. I picked up what I thought was a 621 about a year ago. The case is stamped only with a “N” not N1. Does this make it a 62?


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rlamppa1

rlamppa1

ArboristSite Lurker
Joined
Oct 26, 2016
Messages
27
Location
Minnesota
Well you're welcome....been dealing with these saws since they were current so I pretty much have a handle on them. The 70E is a favorite of mine having spent years logging with one......but that said they have "soft spots" that are electronic based.....which was not such an issue back when you could get parts. Though they were the first of the modern single ring saws with "electronic" igns" the ign system sucked. That is why the late versions of the 70E lost the plastic fan for an alum one and a cyl mounted coil/pickup and a trigger unit under the carb. The conversion is simple but requires changing the cyl as well as the flywheel......but that too is an option if you can find one in a parts saw.....the 621 Jonsereds and 80 and 90 are actually more durable examples with points igns.
I got it running. The little bit I ran it, being I need to get a fan for it, this thing seems like a monster and has unbelievable throttle response compare to any of my 621's. The fan is the least of my worries as far as getting, I will order one of the 3-D printed ones. When the fan broke apart on the previous owner it sheared the plug wire off flush with the coil body. Is it possible to insert a new wire in the existing coil or not. If so, do you have any tricks? I was able to solder the couple short strands coming out of the coil to the old wire. I don't expect that to last long with heat and vibration, but it was good enough to verify that she is a runner. If I can't replace the wire, its finding a good coil that worries me. Can't wait to get it a 100% and stick it in some wood. Thanks for the help.

Regan
 
mogulmasher
Joined
Jun 15, 2018
Messages
965
Location
Rochester, NH
I put one of those 3d printed flywheels on my last 70e. Very quality product, you can't go wrong with one. My current 70e is a newer one with aluminum flywheel. They are a great saw. It always seems like an underwhelming saw to me til I run it in decent size wood and it just powers through easily. I made a mistake selling my first one, my current 70e isn't going anywhere any time soon.
 
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