Jonsered Chainsaws

[Real1shepherd]

Besides the couple of fires we saw, once close to Portland we actually saw blue skies again!! We have literally not seen the sun in over three weeks.

Kevin

 

[sawfun]

First day of fresh air in Portland this morning, along with clouds.

 

[heimannm]

The saw had been worked on before me, someone had used something like Threebond on the base gasket and the intake gasket. The base gasket was ruined when I took the saw apart so I didn't even try to remove the intake gasket between the cylinder and the insulator. I did verify the impulse passage was open to the cylinder so I am comfortable that one is O.K. The carburetor gasket had been sealed with red silicone (Dirko?) and I did my best to get it cleaned up. I'm not sure if I confirmed the passage was open and certainly didn't look at the gasket fit, I just assumed it was good since it was together when I got it.

Since the base gasket was ruined and I didn't have another I did use Dirko HT between the cylinder and the crankcase. I was careful around the impulse passage but I didn't specifically check it to insure it was open once the saw was reassembled. I have a high confidence level is it good to go but I will check it again to be sure. I have used Dirko on a number of 10 Series & Mini Mac McCulloch saws with outstanding results. Dirko is impervious to fuel and oil so it is a good choice for the crankcase

Someone else had just replaced the ring (he bought three from the Greek) but I pulled it apart to check it as it felt like the piston was dragging so I was suspect there was no end gap to the ring. In fact, I found it has maybe 0.012-0.014 clearance after all. I think the dragging I felt was actually the module rubbing on the inside of the flywheel so I dressed the flywheel magnets a bit to remove some burrs and it seemed to turn freely after that. You can really tell when the magnets pass the laminations on the module.

If you don't like silicone, how do you feel about red loc tite? I had to punch out a "bushing" of cured loc tite from each of the cylinder mounting holes just to get the screws to go back through.

I did not get back to the 70E today, I spent a full day on two Mini Macs I am adding to my collection (I am a McCulloch guy first...) but I will devote some additional time to the 70E tomorrow. I am still suspect on the ignition as it should fire & run on a prime through the carburetor even if the carburetor is not moving any fuel.

Mark

 

[heimannm]

I gave it another shot today, indeed the carburetor gasket was incorrect and would not allow the impulse signal to operate the fuel pump.





I made a new oversize gasket to resolve that issue. It was definitely moving fuel after that.



Bad news is the spark is totally unreliable. I did check it again by spinning it with a drill from the clutch side and it will spark for a few seconds then intermittent, then not at all. Guess I will have to find a new module if I want to hear this one run.

Mark

 

[Deleted member 150358]

Seen a used one on eBay $50 obo was a little high on shipping.

 

[Real1shepherd]

As I wrote earlier, the Husky gasket for the Tilly are readily available...or were a yr ago. Cutting one however, is not a big of a deal....just have to make sure that whole impulse channel is covered.

That module, on the other hand, has driven many to drink & fowl women. New SEMs' modules have been made for the Husky 2100, but I haven't heard of one yet for the 70E. What fails inside those SEM's modules is a pulse capacitor from the heat. There was a long running thread in AS, started by an EE about repairing those modules. Essentially, you break into the potting and find a circuit trace....from there you wire a external pulse capacitor ouside the flywheel.

Pretty ambitious repair, but I'm sure the same principles would apply to the 70E SEM's.

You can find used ones alright, but they can soon fail as well. 70E's bring good money dead or alive....just for the parts factor alone. You could bail at anytime and perhaps get your money back. I shudder to think of all the early 70E's that have wound up in landfills because of that early module.

Kevin

 

[Cantdog]

I gave it another shot today, indeed the carburetor gasket was incorrect and would not allow the impulse signal to operate the fuel pump.

View attachment 671020

View attachment 671021

I made a new oversize gasket to resolve that issue. It was definitely moving fuel after that.

View attachment 671022

Bad news is the spark is totally unreliable. I did check it again by spinning it with a drill from the clutch side and it will spark for a few seconds then intermittent, then not at all. Guess I will have to find a new module if I want to hear this one run.

Mark

That gasket is a Very common issue when people who are not familiar with these saws are likely to cause or find when they acquire a non running saw. To bad about the module but if you can't find one for a 66E or 70E keep your eye out for a junk 52E.....same exact module and steel flywheel as the 70E but the wiring to the spark coil connection and kill switch is shorter on the 52E...just have to lengthen them out a bit and you're in business. Many more junked out 52Es around than 66/70E saws.

 

[Cantdog]

Hey Eric!! There's a guy on the main saw forum I been talking to.....he has a 52 he's trying to get going and I been giving him some advise. Has asked about the casting letter/number.....he showed a pic of a 52E that had the regular T4 casting same as the 49SP but his has a T2 casting.....do you have any info on that...I offered some speculation but no firm info to back it up.

 

[heimannm]

I'm waiting for the module for the 70E to arrive, hopefully that saw will run with a spark.

In the mean time I decided I'd clean up this 50 that I acquired a few months back.





Lee H already provided me with a better AF cover.



This saw was as dirty as any I have worked on, loaded with oily sawdust and really run hard and put away wet. This one will not be a GTG saw any time soon as the bearings are rather loose but I would like to hear it run for a minute before putting it up on display with the other Jonsered saws in the collection (2 x 621, 910, 910E, 70E, this 50, and a 2050 that I use on a fairly regular basis).

In addition to the bearings I found a leaky seal on the PTO side, that was an easy fix. I also had to make both intake and carburetor gaskets, replace a number of "non-stock) screws some had substituted, and there is a hole in the oil tank from severe chain rash. The Total bar also has some chips in the rails, I have never seen that on a Total before, just another example of the hard use this one has seen. I am currently struggling with the ignition. It did have a good spark before I took it down for cleaning but I cannot get a spark now no matter what I try. It is frustrating since each components checks, the wiring checks, I really don't know what to look for next.

For what it's worth, in spite of all the obvious hard use, compression is good.



Just for the record, it had spark in this condition.



Clutch side was filthy as well.

I like to be thorough when I clean one up.
​

Mark

 

[heimannm]

I received the "new" module for the 70E today but I've run into a bit of a problem, the flywheel is dragging on the module. Does anyone have advice for getting the flywheel to clear?

I decided to just put the 50 together for now, I don't know why I can't get a spark but it will still look O.K. on display.





Mark

 

[Cantdog]

I'm waiting for the module for the 70E to arrive, hopefully that saw will run with a spark.

In the mean time I decided I'd clean up this 50 that I acquired a few months back.

View attachment 671841

View attachment 671842

Lee H already provided me with a better AF cover.

View attachment 671843

This saw was as dirty as any I have worked on, loaded with oily sawdust and really run hard and put away wet. This one will not be a GTG saw any time soon as the bearings are rather loose but I would like to hear it run for a minute before putting it up on display with the other Jonsered saws in the collection (2 x 621, 910, 910E, 70E, this 50, and a 2050 that I use on a fairly regular basis).

In addition to the bearings I found a leaky seal on the PTO side, that was an easy fix. I also had to make both intake and carburetor gaskets, replace a number of "non-stock) screws some had substituted, and there is a hole in the oil tank from severe chain rash. The Total bar also has some chips in the rails, I have never seen that on a Total before, just another example of the hard use this one has seen. I am currently struggling with the ignition. It did have a good spark before I took it down for cleaning but I cannot get a spark now no matter what I try. It is frustrating since each components checks, the wiring checks, I really don't know what to look for next.

For what it's worth, in spite of all the obvious hard use, compression is good.

View attachment 671845

Just for the record, it had spark in this condition.

View attachment 671846

Clutch side was filthy as well.

View attachment 671847

I like to be thorough when I clean one up.
​

View attachment 671848

Mark

Mark...I suspect when you reassembled your points set you may have got the insulating block and washers out of place that connects the points to the condenser and coil wire.......it's been a while since I've been into those but have installed them out of sequence myself and had a no spark condition for my effort. Sorry I can't more specific.....would have to have one in front of me to see how it's supposed to go....but something to check.

 

[Cantdog]

I received the "new" module for the 70E today but I've run into a bit of a problem, the flywheel is dragging on the module. Does anyone have advice for getting the flywheel to clear?

I decided to just put the 50 together for now, I don't know why I can't get a spark but it will still look O.K. on display.

View attachment 672029

View attachment 672030

Mark

Hmmmmm...that's odd.....the module sits in a machined out place in the case to assure centering to the crank......do you know if it's rubbing around the outside of module like where the magnets are or the top of the module like the flywheel has moved inboard to much?

 

[heimannm]

Contact is between the magnets and the laminations of the module. It is strange indeed...

Mark

 

[Cantdog]

How does the flywheel side main bearing feel? Can you detect any play in that?....

 

[Cantdog]

Contact is between the magnets and the laminations of the module. It is strange indeed...

Mark

I doubt you can shift the module any in it setting but you might try by loosening the screws and trying to move it in the opposite direction. Perhaps you can file a bit off the module mounting plate allowing it to be repositioned away from where it rubs. Never seen that happen before.....must only need a few 1000ths removed....do the magnets look like they have shifted position or are loose?

 

[heimannm]

I just checked it by "painting" the magnets with a red marker and the laminations with a black marker...the laminations were all rubbing one of the magnets so I will try to sand those laminations a bit.

I already tried to loosen the screws and wedge the module over while tightening them again...bearing seem very good. Great minds think alike...

Mark

 

[Cantdog]

Mark...I suspect when you reassembled your points set you may have got the insulating block and washers out of place that connects the points to the condenser and coil wire.......it's been a while since I've been into those but have installed them out of sequence myself and had a no spark condition for my effort. Sorry I can't more specific.....would have to have one in front of me to see how it's supposed to go....but something to check.

Mark...I was not correct on insulating washers etc. for the 50. I'm at the shop now and just pulled an ign system off a 52...I was remembering the 49sp ign which is all together different from the rest. The 50, 51, 52 etc. etc etc. are a much more robust and fool proof setup. Other than cleaning/filing the contacts and making certain the strap that leads to the condenser is not bent down to far and grounding out on the condenser body or the points cover I can't think of any reason why you had spark and then not.

 

[heimannm]

Two sandings were required to gain clearance, the 70E is now a runner!

Photos tonight...

Mark

 

[Cantdog]

I just checked it by "painting" the magnets with a red marker and the laminations with a black marker...the laminations were all rubbing one of the magnets so I will try to sand those laminations a bit.

I already tried to loosen the screws and wedge the module over while tightening them again...bearing seem very good. Great minds think alike...

Mark

LOL I don't know if that's great minds or wishful thinking!! Are the laminations hitting all four magnets or just one??

 

[Cantdog]

Two standings were required to gain clearance, the 70E is now a runner!

Photos tonight...

Mark

Awesome!!!! Nothing like "Hand Fit"....LOL!!! You'll like that old bird!!!!~!