Bad bearing? What happened to the bottom end in this Jonsered?

[retoocs555]

I have a jonsy 2171 on ebay right now and yesterday I went to check the compression... on the 4th pull the saw locked up. You can rotate the engine back and forth from TDC to BDC or close to it and then feel it hit on something.

Previously the saw ran perfect, reved fine and could idle steady through an entire tank of gas.

Any ideas at what went wrong?

Normally this kind of sympton I associate with something dropping down into the bottom of the crank case, a loose bearing, part of a piston etc. But what would have caused that to happen with just 3 starter pulls?

 

[buck futter]

Scott,

I am going to take a wild guess, perhaps something is wrong in the starter cover. If you shake the saw do you hear something rattle? I have seen stuff get in the top of the cylinder and do what you said but never on a saw that runs. I think you should pull the muffler. Then you can see on the top of the piston and then put it up to tdc and try to see what is loose in the bottom.

Buck

 

[retoocs555]

Scott,

I am going to take a wild guess, perhaps something is wrong in the starter cover. If you shake the saw do you hear something rattle? I have seen stuff get in the top of the cylinder and do what you said but never on a saw that runs. I think you should pull the muffler. Then you can see on the top of the piston and then put it up to tdc and try to see what is loose in the bottom.

Buck

I've pulled the starter, the muffler, and the plug. It isn't anything in the top end of the saw, actually sometimes the rotation will go just past tdc before getting stuck.

 

[Dan Forsh]

Probably not your problem, but I rencently had one that would move freely back and to, but wouldn't go through TDC. I found that it had snapped the end off one of the rings which had been jammed into the top of the cylinder and blocked the squish gap. Came to me like that so I'd assume it would have happened when the saw was running. Like I said, probably not your cause, but I pulled the plug, carb and muffler and didn't see anything until I took the cylinder off.

Dan

 

[Dan Forsh]

One thought does occur...

If you look down the plug hole can you see any dents in the piston crown? If it is a piece of ring you might see squareish dinges where it hits.

 

[Lakeside53]

It can happen if you get a main bearing cage collapse. I see it now and then with the nylon bearing cages. The balls then move to one side and pinch the crank. As the others say though - look for other causes.

You can have the cylinder off in 5 minutes...

 

[formersawrep]

I have also seen cases where the crankshaft gets out of center causing it to rub the crankcase. Usually caused by someone hammering on the end of the crank to get the flywheel off.

 

[retoocs555]

I found the culprit. It was at least two of the ball bearings from the clutch side crank bearing.:jawdrop:

Here is a little piece of one.

And a pic of the clutch side of the crankcase, you can see that the ball bearings are missing from the top of the retainer.

So, the question is what might cause this? I hadn't done anything out of the ordinary on this saw. Hadn't touched the clutch or flywheel. Ran this through one tank of gas just fine playing around with it (it isn't everyday I have a fun saw like a 2171 to cut and tinker with.) It wasn't under any particular stress, it wasn't even running.

It had a smooth, even idle before so I didn't even have a thought about any bottom end problems.

 

[RED-85-Z51]

Congratulations on your boat anchor....

But seriously, that sucks. Ive had mowers that Ive run, no problem, crank and run fine, put it down, go back, and its dead...no spark, no compression...you name it.

 

[spacemule]

Just be happy it happened before you shipped it off to the auction winner.

 

[sugarbush]

I found the culprit. It was at least two of the ball bearings from the clutch side crank bearing.:jawdrop:

Here is a little piece of one.

And a pic of the clutch side of the crankcase, you can see that the ball bearings are missing from the top of the retainer.

So, the question is what might cause this? I hadn't done anything out of the ordinary on this saw. Hadn't touched the clutch or flywheel. Ran this through one tank of gas just fine playing around with it (it isn't everyday I have a fun saw like a 2171 to cut and tinker with.) It wasn't under any particular stress, it wasn't even running.

It had a smooth, even idle before so I didn't even have a thought about any bottom end problems.

Here in minnesota we see that often. guy's use there saw to cut ice and it throw's a lot of water, and into the engine. if they put it away wet the bearing's rust up and then next summer when it lock's up they cant figure out what could have happened because last time it ran it worked good.

 

[retoocs555]

Just be happy it happened before you shipped it off to the auction winner.

Yes. Somebody out there would NOT have been a happy camper and I would have had a lot of poo to deal with.



This saw was tuned and running two days ago.

 

[Jonsered Rep]

I have a jonsy 2171 on ebay right now and yesterday I went to check the compression... on the 4th pull the saw locked up. You can rotate the engine back and forth from TDC to BDC or close to it and then feel it hit on something.

Previously the saw ran perfect, reved fine and could idle steady through an entire tank of gas.
Any ideas at what went wrong?

Normally this kind of sympton I associate with something dropping down into the bottom of the crank case, a loose bearing, part of a piston etc. But what would have caused that to happen with just 3 starter pulls?

Did you actually idle the saw through a tank of gas?
If so i have heard of saws overheating because they are not pulling enough air at an idle to keep them cool.
Just my 2 cents those with much more experience than me please correct me if i am wrong

 

[retoocs555]

I did run it through a tank of gas but not all idle. I was just trying to stress that the saw idled along fine. My use was something like: start it up, adjust carb, let the saw warm up, adjust carb, rev a few times, adjust carb, cut some cookies, tweak last few adjustments, cut some cookies, let idle for 2-3 minutes, turn saw off, let sit for a few minutes, fire it back up and then do some random odd and end type cutting.

 

[retoocs555]

Honestly I'm not too suprised something like this happened to this saw.

From all the hundreds of used saws I've seen I'd say any of the recent elux products do not hold up well to commercial use.