Jonsered 670 Super Clean-up

[nlife]

Hi all,

First post here at AS so go easy on me. Father-in-law inherited a Jonsered 670 Super from his late dad and wanted to do some cleanup around the yard with it. It didn't look like it had ever been maintained and he said he couldn't keep it running. It would start, but quickly bog down and die. I offered to take it home and tune it for him. I needed a whole can of brake cleaner to get the oil and grime off of the cylinder head, linkages, and carburetor. I pulled the plastic air filter off and stuffed the carb with paper towel so I wouldn't get anything in it before spraying it. I'm not sure what happened, but at some point in the saws life, someone managed to break the top 4 fins off the right hand corner of the cylinder head.

Next step was to check the H & L jets to see where they were. The previous settings were rich:

• L-3 full turns in to gentle bottom
• H-2 full turns in to gentle bottom

After getting it to idle, I took it out and buried it in some wood to set the jets under load. The new settings are:

• L - ~1.75 turns out
• H - ~1.5 turns out

It's zippy and boy is it ever loud compared to my 38cc Crapsman and 455 rancher! It 4-strokes out of wood, but cleans up nicely in the cut. It sure pulls too. I have no idea what the fuel/oil ratio was that the father-in-law was running, but it was spitting out an extremely rich exhaust. Near had to the chew the air before breathing it. I have run a small amount of Seafoam through half a tank. The new fuel and seafoam seems to have cleaned up the piston since it was BLACK when I started, but now it's a cleaner grey. The spark plug is a tad on the light side of tan, but acceptable. I'm going to check the gap when it cools down.

Issues still remaining are that it's leaking oil to the point where you could paint a house with it and the chain brake doesn't work. I'm not sure if the brake band isn't strong enough or if it's just so covered with oil that it's not able to really get a grip. Heck it could be both. Is there a way to adjust the chain brake? I could also use some help on deciphering the type of replacement chain needed. From what I can make out, it's a 22" bar with 3/8ths pitch. Just not sure on the number of drive links.

It's a fun saw to run, but I don't think I want to run it all day.






Neil

 

[Bob Hedgecutter]

22"should be 76 drive links- but be aware you have an 0.058 bar- not the perhaps more common 0.050 or 0.063.

I wonder if that saw was tuned way rich to try to compensate for an air leak? It is getting to that age where a complete and thorough inspection of all the rubber ware and main seals is perhaps in order.

No way to "adjust" the brake, my guess is the band is broken or worn paper thin. You might find it hard to get genuine Jonsered parts nowadays- but the band from a Husqvarna 61 through to 272 should fit your saw and be easily found.

Nice saws, well worth putting some time into and maintaining.

 

[huskihl]

The band from a 272 may fit if it’s a newer cover. Not sure. Or a 272 clutch cover with brake can be made to work

 

[bama]

22"should be 76 drive links- but be aware you have an 0.058 bar- not the perhaps more common 0.050 or 0.063.

I wonder if that saw was tuned way rich to try to compensate for an air leak? It is getting to that age where a complete and thorough inspection of all the rubber ware and main seals is perhaps in order.

No way to "adjust" the brake, my guess is the band is broken or worn paper thin. You might find it hard to get genuine Jonsered parts nowadays- but the band from a Husqvarna 61 through to 272 should fit your saw and be easily found.

Nice saws, well worth putting some time into and maintaining.

Up here in NW Minnesotahhhhh, the .058 was the standard set up at the shop my dad bought his Jonsereds at. From the 621 to the 920. Just like the air fittings in his shop, I used what I knew and purchased the same fittings.....and BARS for .058. In hindsight, .050 would have been better only for easier availability, but because of my fear of running out of bars that fit, I secured a lifetimes supply of them...

 

[KASH]

Here in NorthWestern Ontario .058 is pretty well standard for Husky and Johnsered Stihl is .050.
Kash

 

[RedneckChainsawRepair]

I can tell ya the band from 272 dont fit the later 670 champ covers. But have read the 272 band will fit some earlier covers. No clue which one.

I had to find a NOS band for my champ later cover.

But then I also test fitted messing around with old 272 cover cut to look like jred cover. Then just bought a aftermarket 272 cover and cut for use. Dont need cut though for use if you dont mine it.

Even the plastic brake handles are a pita to find the ones with right angles to them. Even the inner plastic piece is a pita. So many variations.