Jonsereds 52 help!!

[Yoopermike]

Ok guys, I have from as far as I know is a jonsereds 52 on my bench. It is a buddy of mines saw and he wanted the clutch fixed on the saw as it was locked up. Ie.. chain turned as he pulled the saw over. That's all fixed now but I believe it had another problem. Now as soon as I start the saw it races like it has an air leak somewhere. I've checked and rechecked. I can not find the leak, I've ether'd the saw to death and nothing! My saw manual says carb settings are 1 turn out on the H and L. When I got the saw they were set way out at 2.5. im guessing that those settings matched with the constant drag on the motor via the clutch being locked up somehow masked this problem?? I am pulling my hair out as I've torn the saw apart at least a dozen times. I've checked crank seals, carb gaskets and the base gasket. What am I missing??

 

[Cantdog]

Ok guys, I have from as far as I know is a jonsereds 52 on my bench. It is a buddy of mines saw and he wanted the clutch fixed on the saw as it was locked up. Ie.. chain turned as he pulled the saw over. That's all fixed now but I believe it had another problem. Now as soon as I start the saw it races like it has an air leak somewhere. I've checked and rechecked. I can not find the leak, I've ether'd the saw to death and nothing! My saw manual says carb settings are 1 turn out on the H and L. When I got the saw they were set way out at 2.5. im guessing that those settings matched with the constant drag on the motor via the clutch being locked up somehow masked this problem?? I am pulling my hair out as I've torn the saw apart at least a dozen times. I've checked crank seals, carb gaskets and the base gasket. What am I missing??

Hard to make a call like this long distance but here are a few suggestions....

First, have you backed the "T" (throttle adjustment) off to let it idle down? Perhaps a silly question...but need to start with the basics....

Second concerns the carb gasket between the carb body and the isolation block......does it have the correct gasket...the diamond shaped ones that come in the carb kit won't work It will not cover the entire impulse passage leaving an air leak. You need a gasket that is large enough to cover this passage.....Husky 61,66,266 etc. will work fine since the Jonsereds gasket is NLA. Also when you have the carb off make sure the (9 ?) bolts that hold the isolation block to the cyl are tight.

Third, is the throttle plate hanging up in the bore and not closing completely and evenly. With the carb removed the plate should close completely...if not loosen the plate screw and let it self adjust. Another potential problem area is the cyl base gasket...they are very thin paper (like 0.007") and can blow out causing an air leak too......when this happens it's usually a no start situation but a small leak might give you an engine racing problem.

Just some thoughts to ponder and things to check out.......you said it was a 52 and not a 52E ...if so, being a points system it could be a timing issue of one type or another....but I would eliminate the suggestions made first.......start easy and work toward hard is the best method, I find.....good luck and let us know what you find....

 

[Yoopermike]

Yep, idle screw is backed off completely. I will check the throttle plate. I am assuming it is a 52 as it does not look like the 52e. I believe the 52e is all red. This is red with a black cover. All the others that came close had chain breaks, this does not.

 

[taplinhill]

52 and 52E both have black covers, as does the 51. The 49SP is the only one with a red cover, but they can be interchanged. Chain brakes were optional on most saws, so don't use that as an identifier.

 

[Four Paws]

Check out the oil pump adjustment on the bottom of the saw. it is a screw in sleeve setup with o-ring and lots of potential for leaks.

 

[Yoopermike]

Well then I am at a loss for identification other than I know it is not a 52e as it has points.

 

[Rx7man]

If you can't find a leak, look at the carb. Back off the T screw until the carb lever doesn't even touch it, make sure the linkage to the trigger isn't too long!

 

[Four Paws]

It's the oiler adjustment screw, I know it is.

 

[Yoopermike]

It's the oiler adjustment screw, I know it is.

How would the oiler adjustment screw cause an air leak into the crank?

 

[Cantdog]

Well then I am at a loss for identification other than I know it is not a 52e as it has points.

Easiest way to tell the difference regardless of cover color is the 49sp has the spark coil mounted to the cyl....both the 52 and 52E it's mounted in the recoil cover.

 

[Four Paws]

How would the oiler adjustment screw cause an air leak into the crank?

Because it opens into the crank case. Check your oil pump o-rings, too.

 

[Cantdog]

How would the oiler adjustment screw cause an air leak into the crank?

It is o-ringed to the case with one o-ring....if that should fail it will cause an air leak.....personally I have not seen one fail...but that does not mean it shouldn't be considered....as well as the other things mentioned.

 

[Iain Telfer]

Hard to make a call like this long distance but here are a few suggestions....

First, have you backed the "T" (throttle adjustment) off to let it idle down? Perhaps a silly question...but need to start with the basics....

Second concerns the carb gasket between the carb body and the isolation block......does it have the correct gasket...the diamond shaped ones that come in the carb kit won't work It will not cover the entire impulse passage leaving an air leak. You need a gasket that is large enough to cover this passage.....Husky 61,66,266 etc. will work fine since the Jonsereds gasket is NLA. Also when you have the carb off make sure the (9 ?) bolts that hold the isolation block to the cyl are tight.

Third, is the throttle plate hanging up in the bore and not closing completely and evenly. With the carb removed the plate should close completely...if not loosen the plate screw and let it self adjust. Another potential problem area is the cyl base gasket...they are very thin paper (like 0.007") and can blow out causing an air leak too......when this happens it's usually a no start situation but a small leak might give you an engine racing problem.

Just some thoughts to ponder and things to check out.......you said it was a 52 and not a 52E ...if so, being a points system it could be a timing issue of one type or another....but I would eliminate the suggestions made first.......start easy and work toward hard is the best method, I find.....good luck and let us know what you find....

Thanks for all of this. It is great to see there are other enthusiasts out there with these wonderful saws and trying to get them to work again.
I have much the same problem with my 52E converted back to the old points system as the electronic cem is now out of date. They just don't make them like this anymore. Easy saws to maintain and fix but parts are hard to find.
Many Thanks.
Iain