Jonsered 670 Idle adjustment?

[Ray Bennett]

I found a nice 670 (my first non Sthil) It runs great lots of power for a small saw. I think it is gonna replace my 036 for limbing. Only problem Is I cant quite get the Idle right. It has a new pug and air filter and clean gas. With the idle screw any where from 3/4 turn to 1 1/4 turn out it Idles nice but the chain wants to roll. When I adjust the other idle screw to adjust that problem the chain stops but the saw will not Idle as well and some times cut off after running. I have never had a problem with my stihls doing this but they are much newer. What am I doing wrong? Does any one know what jonsered recommends all three screws be set at?

 

[HiOctane]

Your Lo and Hi should be set at 1 turn out for initial setting.After,you will need to set the Hi to get "the right sound".The idle screw,there is no specific ajustment setting,you just set it to get a good rpm for your idle.If you think yout idle rpm is ok and the chain is still turning,maybe you got a dry bearing sprocket or clutch spring need to be replaced.Does the idle goes up and down or its steady ?If the idle fluctuates a lot,then it could be an air leak .

 

[Ray Bennett]

Your Lo and Hi should be set at 1 turn out for initial setting.After,you will need to set the Hi to get "the right sound".The idle screw,there is no specific ajustment setting,you just set it to get a good rpm for your idle.If you think yout idle rpm is ok and the chain is still turning,maybe you got a dry bearing sprocket or clutch spring need to be replaced.Does the idle goes up and down or its steady ?If the idle fluctuates a lot,then it could be an air leak .

The idle is very steady sounds great and double checked with a tach, started at 1 turn out and finished with 1 1/8 out. H is set at just over 1 1/2 turns out, a little rich but where I like for longevity of the saw. Also double checked with a tach and safe. Now the final screw which I normally turn until the chain rolls then back off till it stops has to be turned 5 turns out to stop the chain from rolling. Going this far causes the saw to idle slow and staul when I am on and off the gas a lot like when I'm limbing. 4 to 4 1/2 turns out makes the saw run perfect but the dang chain rolls. I will check the bearing sprocket and clutch closer tomorrow. But for now what do ya think of my idle adjustments?

 

[SawTroll]

...If you think yout idle rpm is ok and the chain is still turning,maybe you got a dry bearing sprocket or clutch spring need to be replaced. .....

Agree!

Here is a workshop manual, covering the 670 (670 Champ really) and several other Jreds.

What version of the 670 is the saw in question?

 

[Ray Bennett]

Im not sure on what versions are out there, Mine is a 1995 model, no decompression valve, chain brake is on the outside of the sprocket. Does not say champ on the saw. Does any of that help?


I did test the compression just to rule that out as an issue. It was 150

 

[SawTroll]

Im not sure on what versions are out there, Mine is a 1995 model, no decompression valve, chain brake is on the outside of the sprocket. Does not say champ on the saw. Does any of that help?


I did test the compression just to rule that out as an issue. It was 150

I believe the Champ and The West-Coast (based on the Champ) were the only versions still made at that point, but I could be wrong.......

Anyway, it should be a Super or Champ if it beats the 036 with a sizable margin..........

 

[Ray Bennett]

I believe the Champ and The West-Coast (based on the Champ) were the only versions still made at that point, but I could be wrong.......

Anyway, it should be a Super or Champ if it beats the 036 with a sizable margin..........

What should I look for to separate the two? The muffler is an open can with a real nice exhaust opening, No emissions stuff choking this saw out.

 

[SawTroll]

What should I look for to separate the two? The muffler is an open can with a real nice exhaust opening, No emissions stuff choking this saw out.

The label that say what it is, is located on the flywheel cover, but often missing.
Maybe or maybe not, there could be a clue on the serial number plate?

I don't really know what else to look for......

Here is an interesting tread.

 

[HiOctane]

The idle is very steady sounds great and double checked with a tach, started at 1 turn out and finished with 1 1/8 out. H is set at just over 1 1/2 turns out, a little rich but where I like for longevity of the saw. Also double checked with a tach and safe. Now the final screw which I normally turn until the chain rolls then back off till it stops has to be turned 5 turns out to stop the chain from rolling. Going this far causes the saw to idle slow and staul when I am on and off the gas a lot like when I'm limbing. 4 to 4 1/2 turns out makes the saw run perfect but the dang chain rolls. I will check the bearing sprocket and clutch closer tomorrow. But for now what do ya think of my idle adjustments?

The idle screw,not the L one has no "predetermined" setting.I mean,don't worry if its 3 or 6 turns out,it doesnt matter.Set it to have a good rpm for your idle and forget the numbers of turns.I think at 1 1/2 on your H gives you a lot of blubbering at hi speed,you could tighten a bit to get a better running engine and better response too.Your LO sound pretty close to normal though.

 

[royta]

Agree!

Here is a workshop manual, covering the 670 (670 Champ really) and several other Jreds.

What version of the 670 is the saw in question?

Is there anything like that for the Jonsered 525? I'm chasing down some problems on mine. Thanks.

 

[romeo]

I would bet the clutch spring is weak causing it to engage to soon. Change the clutch and the problem should go away.

 

[HiOctane]

Is there anything like that for the Jonsered 525? I'm chasing down some problems on mine. Thanks.

The service manual is no longer available from Jonsered for your saw.

 

[SawTroll]

Is there anything like that for the Jonsered 525? I'm chasing down some problems on mine. Thanks.

I have never seen one, sorry!

 

[Ray Bennett]

Thanks for the help, I will take a close look at the clutch and bearing as soon as possible and let ya know.

Troll, that manual is great, thanks a million. I owe ya a beer.