Jonsered 70E problems after 15 min running great

[Overlooker]

And if the clutch-side seal is bad, what are the chances that the bearing is any good? O

 

[Cantdog]

After lots of testing, I'm quite sure I found the culprit. While the carb held vacuum at 15, and no soapy bubbles were blown on the flywheel side of the crank, the clutch side leaks like a seive. How do I pull that clutch? Three screws and a three-arm puller?
View attachment 1088954
Thanks, O

How did you get the flywheel off to check that seal? The SEM module goes all the way around the crankshaft...no way to get soapy water in there or see with the flywheel on.

You will need to make a plate puller like the one of ones in the pic. The rough black one I made years ago and works fine. The shiny one a fella in the Jonsered stickey made for me......I swapped him some 70E parts for it. Works better than mine as you only tighten one bolt instead of three. Both will pull any flywheel or clutch on the 49SP through 90 saws.

 

[hotshot]

After lots of testing, I'm quite sure I found the culprit. While the carb held vacuum at 15, and no soapy bubbles were blown on the flywheel side of the crank, the clutch side leaks like a seive. How do I pull that clutch? Three screws and a three-arm puller?
Thanks, O

Don’t check a carb inlet w/ vacuum, you probably ruined the Viton inlet needle tip now…

This might fit if you can’t make one, or don’t already have a steering wheel puller.

https://www.googleadservices.com/pa...kWoFHYxKAwcQwg8oAHoECAUQEA&nis=2&dct=1&adurl=

 

[Cantdog]

Don’t check a carb inlet w/ vacuum, you probably ruined the Viton inlet needle tip now…

This might fit if you can’t make one, or don’t already have a steering wheel puller.

https://www.googleadservices.com/pa...kWoFHYxKAwcQwg8oAHoECAUQEA&nis=2&dct=1&adurl=

Yep that would work too.....

 

[Overlooker]

This might fit if you can’t make one, or don’t already have a steering wheel puller.

That looks like it would work. I have a steering wheel puller that should try first. It might be too large.

How did you get the flywheel off to check that seal?

I adapted a two-arm seal puller to pull the fly wheel. Now I need a three-arm puller for the clutch. Thanks to all for your input. Now just need to locate a new seal. O

 

[Cantdog]

If you can't find OEM I've had good luck with these. TCM part # is the seal size.....
Set them in just flush......they are one MM thicker than OEM but fit fine otherwise.


One other thing......try not to remove the clutch spring and shoes from the clutch spyder......can be quite a struggle reinstalling the spring.

Not undoable but better left intact. Clutch can be pulled with the shoes installed. Thread three bolts into the legs of the spyder to pull with.

 

[Overlooker]

If you can't find OEM I've had good luck with these. TCM part # is the seal size.....
Set them in just flush......they are one MM thicker than OEM but fit fine otherwise.


One other thing......try not to remove the clutch spring and shoes from the clutch spyder......can be quite a struggle reinstalling the spring.

Not undoable but better left intact. Clutch can be pulled with the shoes installed. Thread three bolts into the legs of the spyder to pull with.



View attachment 1089005

I think I can get my steering wheel puller to work if I can find longer bolts with the right thread. Thanks so much for the part info. I will get one ordered. O

 

[Overlooker]

You will need to make a plate puller like the one of ones in the pic. The rough black one I made years ago and works fine.

Made my own puller from a scrap of steel and some M5 screws.


My center bolt was just a 1/4-20 #5 bolt that didn't fare well, but it got the job done. Redid the pressure test with the clutch out of my line of sight and confirmed the leaky seal. Now I need to order a new one. Thanks again for your help. T-A

 

[Overlooker]

If you can't find OEM I've had good luck with these. TCM part # is the seal size.....
Set them in just flush......they are one MM thicker than OEM but fit fine otherwise.


One other thing......try not to remove the clutch spring and shoes from the clutch spyder......can be quite a struggle reinstalling the spring.

Not undoable but better left intact. Clutch can be pulled with the shoes installed. Thread three bolts into the legs of the spyder to pull with.



View attachment 1089005

I just got two new seals today (UPS). When I ordered them, the bill was $10.50, with tax, but S&H was yet to be determined. When they arrived today, I checked my credit card and found that the S&H fee was $18.00! I guess I shouldn't be surprised, and, as long as it's the right seal (I'll have a spare.), I'll enjoy the saw and forget about the price. All for a saw that cost me $5! Thanks again for your help. O

 

[Overlooker]

If you can't find OEM I've had good luck with these. TCM part # is the seal size.....
Set them in just flush......they are one MM thicker than OEM but fit fine otherwise.


One other thing......try not to remove the clutch spring and shoes from the clutch spyder......can be quite a struggle reinstalling the spring.

Not undoable but better left intact. Clutch can be pulled with the shoes installed. Thread three bolts into the legs of the spyder to pull with.



View attachment 1089005

I got the new seal in, almost as planned. It ended up being about a millimeter deeper than flush, but everything moved freely, and it passed vacuum & pressure tests. So, after reassembly, it ran and idled perfectly. I made two cuts in an 18" walnut log, and then it refused to idle down. Back to square one! Is the other crank seal the same size? I can't get the hot saw set up for testing without having it cool down in the interim. Maybe I should just replace the second crank seal. The one I replaced was very hard and brittle. Thoughts? Thanks, O

 

[Cantdog]

I got the new seal in, almost as planned. It ended up being about a millimeter deeper than flush, but everything moved freely, and it passed vacuum & pressure tests. So, after reassembly, it ran and idled perfectly. I made two cuts in an 18" walnut log, and then it refused to idle down. Back to square one! Is the other crank seal the same size? I can't get the hot saw set up for testing without having it cool down in the interim. Maybe I should just replace the second crank seal. The one I replaced was very hard and brittle. Thoughts? Thanks, O

I always replace both at the same time. If one is bad the other is surely not far behind.

Yes they are the same size...

 

[Overlooker]

Today I replaced the second seal and was disappointed to find that the old one was not dry and brittle like the first one that I replaced. After reassembly, the saw started easily and idled all the way to the timber. As I began cutting, it promptly began to bog at WOT, only willing to maintain reasonable RPM at half throttle. Without much optimism, I took a screwdriver to the L screw and gave it a quarter turn counterclockwise. Problem solved! From then on it cut and idled perfectly. My goal was to run the saw out of gas, but instead, I ran out of gas! I'll take it out to cut more another time, and, if all goes well, I'll declare it a runner and park it on rhe shelf with all my old Homies.

I'll finish my down walnut tree removal with my much lighter 036! Thanks, Cantdog, for staying with me on this project. O

 

[Overlooker]

"and park it on rhe shelf with all my old Homies."


Starting at the top: two Super XLs, an XL 12 and a third Super XL, an XL 12 survivor (all I've done is a little cleaning), my Jonny 70E, and my XL 923/31in Windsor bar. All are runners except the survivor XL 12, which I plan to leave as-is. Sorry my museum space isn't more attractive! O

 

[Overlooker]

Today I cut, loaded, split, and stacked another cart-full of walnut, and I couldn't be much happier! Altogether I had the Jonny running for only about 12 minutes, but that was plenty long enough for me to believe all my efforts (and all the advice I got along the way) were well worth it! Next, I will prepare this saw for shelf-life and put one of my Homies, likely a Super XL, into service to give it some exercise. I'd like to eventually rotate through all my old runners to make sure they still check out okay. Here are my Super XLs:

Future projects include an EZ, an EZ Automatic, and a Super EZ Automatic. Time will tell how many of them I get running. Thanks for watching! O