Determining the model year of Jonsereds 621

[aroy1234]

Hello all,

I was wondering if anyone would be able to tell me the age of my late grandfathers Jonsereds 621 chainsaw. I’m looking to possible restore it soon. Any information on this particular saw would be greatly appreciated. Let me know if I need to provide more pictures. Serial number- 853485

 

[John Stryker]

http://www.acresinternet.com/cscc.n...af40002b8f7/11784e055d87ccf388256b690079200b/

 

[aroy1234]

http://www.acresinternet.com/cscc.n...af40002b8f7/11784e055d87ccf388256b690079200b/

Thank you, sir!

 

[Cantdog]

View attachment 1031804Hello all,

I was wondering if anyone would be able to tell me the age of my late grandfathers Jonsereds 621 chainsaw. I’m looking to possible restore it soon. Any information on this particular saw would be greatly appreciated. Let me know if I need to provide more pictures. Serial number- 853485

No way to actually tell the year as the serial number is not a code....just a production number......if you can post a pic of the recoil side I can tell you whether it's early or late but that's as close as you can come. I'm gonna say by the black and white "Jonsereds 621" sticker shown in this pic it's an early one....if that in fact is original...the later stickers were red and white lettering while the early ones were black and white lettering.

Oh...and welcome to the site!!

 

[aroy1234]

No way to actually tell the year as the serial number is not a code....just a production number......if you can post a pic of the recoil side I can tell you whether it's early or late but that's as close as you can come. I'm gonna say by the black and white "Jonsereds 621" sticker shown in this pic it's an early one....if that in fact is original...the later stickers were red and white lettering while the early ones were black and white lettering.

Oh...and welcome to the site!!

Thanks, Cantdog! I was able to pull it apart today, clean up the carb and put some fresh fuel through her and she fired! Now time to put it to good use. He also had a Jonsered 90, but my uncles got that one. Definitely solid machines.

 

[aroy1234]

Hey guys,

I’ve been using the saw the last few days whenever I get the chance. Is it normal for this particular saw to bog when it’s cold? I let the saw run for a minute or two before I try and use it but even then it bogs and I have to feather the throttle just right to get it to light up. After cutting a bit, it runs fine. Also, is there anything I should do maintenance-wise besides sharpening the chain? Really want to keep this saw going for as long as possible.

 

[John Stryker]

Cold air is more dense, so you may need to open up the low jet a wee bit. Basic saw maintenance that I do is clean out the bar groove regularly and oiler hole in the bar, occasionally dress the bar rails, and clean the air filter. Also you can check that the fuel lines aren't cracked or hard, and the fuel filter is not plugged up.

 

[Cantdog]

Yep.... open up the "L" side just a bit which may slow the idle down a some so you have to advance the "T" setting just a bit to get your idle back up to normal.

 

[Cantdog]

Another bit of maintenance is that the clutch end of the crankshaft has a passage to the bushing that the clucth bearing rides on so you may grease the bearing through the end of the crank without dismantling the clutch drum.

 

[aroy1234]

Such great information! Thanks to you both, I’ll look into all of this today and come back with my findings. I’ve noticed that parts are somewhat hard to find if I end up needing them. Not surprised as its a 50 year old saw. All more the reason to keep it in good shape LOL

 

[Cantdog]

The 621 is a legend and a very powerful 56cc saw......basically the first of the "Modern Chainsaws".....quiet and with good AV system and also one of the first to not exhaust in your face.....most run a 20" bar with 3/8" full chisel chain all day and never break a sweat......so far ahead of other saws of the time it's not even funny.....

 

[aroy1234]

The 621 is a legend and a very powerful 56cc saw......basically the first of the "Modern Chainsaws".....quiet and with good AV system and also one of the first to not exhaust in your face.....most run a 20" bar with 3/8" full chisel chain all day and never break a sweat......so far ahead of other saws of the time it's not even funny.....

Cantdog, I’ve done some research on these saws through this forum and it seems you know everything about them! LOL. I’m very happy I was able to get this saw from my grandfather and I’ll definitely hold on to it forever. Today I looked over the fuel system and the lines seemed to be in surprisingly good shape. As far as tuning the carb, I am probably going to end up removing/rebuilding it so I will tune it once it’s back together. (don’t worry I saw what you said on another thread about the gaskets in aftermarket rebuild kits causing an air leak. Definitely going to source a NOS gasket if possible). Also, I wasn’t quite able to figure out greasing that bearing on the clutch side. It does have a 20” bar, so it seems my grandfather knew what he was doing!

 

[Cantdog]

Cantdog, I’ve done some research on these saws through this forum and it seems you know everything about them! LOL. I’m very happy I was able to get this saw from my grandfather and I’ll definitely hold on to it forever. Today I looked over the fuel system and the lines seemed to be in surprisingly good shape. As far as tuning the carb, I am probably going to end up removing/rebuilding it so I will tune it once it’s back together. (don’t worry I saw what you said on another thread about the gaskets in aftermarket rebuild kits causing an air leak. Definitely going to source a NOS gasket if possible). Also, I wasn’t quite able to figure out greasing that bearing on the clutch side. It does have a 20” bar, so it seems my grandfather knew what he was doing!

It seems you are watching!! As I've said before a Husky 61/266 etc gasket is an option that will work.

You may have to take the drum off the clutch to clean the passages and the holes in the bushing as they tend to get crudded up over time.......one thing to remember is that bearing is only in use while at idle, so not as in need of lube as some others.

 

[Cantdog]

Perhaps I should explain a bit further on the drum bearing greasing thing. In the end of the crankshaft there is a taper for centering the shaft...like in a lathe. At the bottom of that taper is a hole drilled in the center of the shaft......this extends in to roughly the center of the clutch bearing bushing and has another hole drilled perpendicualr to the first. You need a needle type grease gun like you would use to grease your bar tip......you inject grease into the hole at the bottom of the taper and it travels to the inside of the bushing. The bushing itself has three hooles in it which allows the grease to get evenly into the bearing. It doesn't take a lot of grease....don't over do it.

 

[aroy1234]

Perhaps I should explain a bit further on the drum bearing greasing thing. In the end of the crankshaft there is a taper for centering the shaft...like in a lathe. At the bottom of that taper is a hole drilled in the center of the shaft......this extends in to roughly the center of the clutch bearing bushing and has another hole drilled perpendicualr to the first. You need a needle type grease gun like you would use to grease your bar tip......you inject grease into the hole at the bottom of the taper and it travels to the inside of the bushing. The bushing itself has three hooles in it which allows the grease to get evenly into the bearing. It doesn't take a lot of grease....don't over do it.

cantdog, just saw this reply. Thank you. Happy thanksgiving by the way, i will definitely look into this. Would you be able to tell me what this highlighted part is?

 

[Cantdog]

I believe that is part of the optional chain brake.....not actually part of the chain brake itself but the earliest set ups not only applied a drag shoe on the clutch drum when activated, but also grounded out the ign to stop the engine.....this is the ground point for that and the wire would have run from it back to the switch........which is why the old switches had two spade terminals when only one is needed to stop the saw by the switch. When the brake flag was in the tripped position the handle would actually contact the screw that holds the item in place to complete the ground.

 

[aroy1234]

Great info, Cantdog! The reason I asked is because I’ve been trying to locate the source of what I’m assuming is a fuel leak pooling up next to the side of the cylinder right next to that piece for the chain brake that you identified. I am not able to take a better picture since I’m currently in Vermont for the holidays. Attached is a picture I took before I removed the carburetor. Currently waiting for the rebuild kit to arrive. Circled you can see for reference where the fuel is pooling up. I am very confident that it is not bar oil. Hard to confirm as everything is very dirty.

 

[Cantdog]

Great info, Cantdog! The reason I asked is because I’ve been trying to locate the source of what I’m assuming is a fuel leak pooling up next to the side of the cylinder right next to that piece for the chain brake that you identified. I am not able to take a better picture since I’m currently in Vermont for the holidays. Attached is a picture I took before I removed the carburetor. Currently waiting for the rebuild kit to arrive. Circled you can see for reference where the fuel is pooling up. I am very confident that it is not bar oil. Hard to confirm as everything is very dirty.

About the only place fuel can come from in that area is from the tank vent line end just below there......perhaps blown up by cooling air from the flywheel.

 

[aroy1234]

About the only place fuel can come from in that area is from the tank vent line end just below there......perhaps blown up by cooling air from the flywheel.

That’s interesting. Not sure why fuel would be coming out of the vent line. The fuel line coming from the tank was pretty rough but the vent line seemed to be fine. Replacing both for peace of mind. The breather was not plugged at all, carb seemed pretty clean for its age. Removed welch plugs and even those screens weren’t even plugged up much. I guess we’ll see what happens once it’s all back together! Thanks, Cantdog.

 

[aroy1234]

About the only place fuel can come from in that area is from the tank vent line end just below there......perhaps blown up by cooling air from the flywheel.

UPDATE: still waiting on the carburetor rebuild kit (thanks USPS) but I did find a sweet deal on this Jonsereds 70e from one town over! Runs awesome and it seems to be very clean for its age. The bar that’s on it right now was originally supposed to go on the 621, but the 70e had an 18” bar and figured the new 20” would be a better fit. Currently waiting on a chain. I’m stoked!