Bringing back a 621 Jonsereds

[Stihl 041S]

Well....here it is complete......you can see what I meant about the top cover showing a lot of wear.....especially from starting and by comparing it to the trigger handle wear which is a prime indicator to me on these old all metal saws of just how many hours it has been held/used.

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The wear is honest. Like nice holster wear on a Colt SAA.

No way to fake it. It looks right.

 

[Cantdog]

The wear is honest. Like nice holster wear on a Colt SAA.

No way to fake it. It looks right.

True enough.....but I believe this is not the original but a used one...much more used than the saw itself...

 

[Cantdog]

This is a pic of what Niko was talking about concerning the top handle clamp on the 62 as opposed to the 621.....I did not know this....but I have never even seen a 62 either.

 

[SawTroll]

True enough.....but I believe this is not the original but a used one...much more used than the saw itself...

It surely looks that way.

 

[Stihl 041S]

Perhaps a piece of large Diameter Heat shrink is in order?

 

[Cantdog]

Perhaps a piece of large Diameter Heat shrink is in order?

Now were would I get something like that??......Oh wait.......

 

[SawTroll]

This is a pic of what Niko was talking about concerning the top handle clamp on the 62 as opposed to the 621.....I did not know this....but I have never even seen a 62 either.

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There was a slight difference between the models regarding the shape of the "edges" of the top covers as well - at least I haven't seen any exceptions from that so far.

Your attachment remind me that there is no real proof that there wasn't an "overlap" in time between 62 and 621 production - but that manual/picture really is the only indication I ever have seen (I have seen it before, once reminded).

 

[heimannm]

Well I finally have the internet working at home again, so here are some photos of the clutch removal tool. The small hook engages the clutch spider through the slot in the drum to lock it, allowing you to turn the nut with the same 17 mm wrench you used on the bar nuts.







This one has been in my possession since 1981.

Mark

 

[Cantdog]

Nope .....I was right.....never seen one of those Mark......cool tool....more good info!!

 

[SawTroll]

Looks like a much better option than using a piston stop.

 

[Sty57]

Well I finally have the internet working at home again, so here are some photos of the clutch removal tool. The small hook engages the clutch spider through the slot in the drum to lock it, allowing you to turn the nut with the same 17 mm wrench you used on the bar nuts.

View attachment 516720

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View attachment 516722

This one has been in my possession since 1981.

Mark

That thing is awesome, why hasn't that been the standard on every saw after.

 

[Cantdog]

That thing is awesome, why hasn't that been the standard on every saw after.

Because it's simple and easy......and works to good.....can't have that.....then every shumck could change their own rim drives or set their own points!!!

 

[Cantdog]

So.... back to the project, this will get a bit more interesting....the rebuild is good info for folks with an interest in the 621 but the proof is in a running saw not just one bolted together. I got the saw all together, fueled and oiled.....put my tuning screwdriver in my pocket and stepped outside to start her up.......well that didn't go well....no start....not even a pop. Back to the bench it went....found it to be a no spark issue. Fortunately having more than one of these saws helped with trouble shooting......first I removed the top cover. The spark coil is located in the cover so by simply swapping the cover onto a known working ign system on a different saw was an easy and quick way to find that there was no problem with the coil, plug wire or plug connection. Next I removed the flywheel and points box cover....the generating coil tested OK....the points I had already filed and set ....they were still gapped correctly....so that left the condenser which I replaced with a NOS one and reassembled the saw enough to check for spark again.....it had spark....not great spark but spark none-the-less. Finished putting everything back together and tried starting it again.....nope...not even a pop....back to the bench...check again for spark......nope.....????? Time to stop now.....walk away from the saw. So I slept on it and yesterday morning had a plan formulated...sort of. When working on anything I have learned over the years to go slow and eliminate completely the simplest parts that are easiest to get to that have been yet untouched. In this case the wire that I repaired had not been inspected the entire length. So I pulled the flywheel again and the entire timing plate and removed the wire.....of course it was in good condition....cross that off the list. So that leaves the timing plate itself and generating coil as the points had been attended too and the condenser already replaced. I got looking at all the parts and on close inspection found what I determined to be a fairly large amount of oxidization of the alum parts and some rust/dirt buildup on the iron parts, like the laminations that held the generating coil. I cleaned the timing plate where it contacted the case and cleaned the case itself. Next I cleaned the timing plate where the points are located and cleaned the lamination edges that the flywheel magnets run by. Now I have a NOS generating coil and numerous used ones but they are a little difficult to replace as one wire has to be soldered to the heavy iron laminations of the coil carrier.....not undoable but it takes a lot of concentrated heat to get the iron hot enough to melt the solder without melting the plastic insulation on the coil itself......a common electrical soldering gun won't even begin to touch it......again the coil did not have an open circuit so I'll try this general total cleaning first as I'd rather not go there if it isn't necessary.

 

[Cantdog]

So I put the saw all back together.....even used a NOS wire retainer....not that there was anything wrong with the original but I have a packge to NOS ones so what the hey!!! Returned the timing plate again to the original timing setting via the marks I previously put on the case and plate.

 

[tbone75]

Sure hope that did the trick ?

 

[Cantdog]

That did the trick...good bright spark.....saw started on the first pull....I guess from the residual gas still in the motor from the two previous starting attempts. However there are a couple more issues yet. After I warmed it up and tuned the carb by ear and shut it off the recoil refused to work....the pawls had opened up and stayed out. The pawls get sticky sometimes due to debis and or rust. The circlips that hold the pawls on are a real PITA...very strong and are very hard to get off with losing or distorting to the point of uselessness. Managed to get one off and found the pawl to be free of debris or rust....nicely loose..????? Then I got looking at what the heck was causing them to stick.....then it dawned on me....whoever had been in there last had hooked the spring ends over the two nubs that are cast into the flywheel to limit just how far the pawls can move outward. Though this loads the springs more it changes the entire relationship of how everything works together. When the pawls extend to max the springs bunched up below the pawl and jambed the pawl. I did not get a pic of how they were but you can the nubs and now where the spring ends are supposed to be.....moved back against the adjacent fan blade to each spring. I put the one back together and everything works perfectly.......again I overthought the issue/problem but caught myself before I had to do twice as much work for nothing. I cannot overstate the saying "NEVER overlook the obvious".....

 

[Cantdog]

HaHaHa John was you reading my mind or what???

 

[tbone75]

HaHaHa John was you reading my mind or what???

Been into things like that myself . LOL Lots of headaches never seeing how obvious it was ! LOL

Think its ready for the test run ? LOL

 

[Cantdog]

Been into things like that myself . LOL Lots of headaches never seeing how obvious it was ! LOL

Think its ready for the test run ? LOL

No not quite yet.....another issue to deal with now that it starts and runs OK. Someone did something and I can't understand why.

The front bar stud was cranked way to far into the case......so far in fact I could only get about a turn and a half on the threads and as I pondered that I noticed that what I had taken for really nice bars nuts were indeed flawed. Someone had scrunched, mechanically I presume, three equidistant flats on the nut. Kind of a reverse knurling so that the nut size was reduced enough to create an interference fit to the point where it overcame the threads in the case. So I had to double nut and heat the case to get the stud back out. Cleaned both threads thoroughly with acetone and set at the correct depth and locked with some really heavy duty red locktite (that someone gave me LOL!!). Then replaced both bar nuts with used stock ones. The offending nut is the one on the left.

 

[Cantdog]

I assume you meant to say 220?

Apart from that, I am of course most curious of the serial number in the one that says Jonsereds 621 in italics on it, as that should be a quite early one (unless the bracket with the label has been swapped at some point). As you likely know, the earliest ones said Raket 621, but I don't know when it changed (neither time or serial number).

Yes Niko I did mean 220 lbs. Thanks! I will edit that. I will get you the numbers later today when I go to the shop.

This was the compression just after the first start, having burnt the assembly lube off.