Issues with Echo 620P tensioner

[martym14]

I’ve had the 620p for over a year and love it. Only issue I’ve had is with the chain tensioner bending, while using the 27” OEM bar. It’s happened twice now. The clutch cover bolts have come off when this issue happens as well. No issues with the 20” bar.
After the first time I became paranoid about constantly checking bolts and chain tension and hadn’t had a problem til yesterday. I constantly clean the saw and sharpen the chain. The saw is not used professionally, so it’s not a wear and tear issue. Oiler seems to work but the cover and bar have been hot when this happens. Anyone know why this could be happening? I wondered if this bolt was not sturdy enough for the 27” bar or if there was a recall but couldn’t find one.

 

[coffeebrk]

Are you lifting up on the bar tip when adjusting tension and tightening bar nuts?

 

[martym14]

I am. Sorry, meant to include that but as well.

 

[Jwilliams]

I’ve had the same thing happen to me twice with my 620

 

[martym14]

Thank you for sharing that! Glad I’m not going crazy. I emailed Echo wondering if there was a recall. My serial number is much higher than what the correct bolt is listed for.

 

[rahtreelimbs]

So far no issues on any of my Echo 620's and Shindaiwa 600SX's.

 

[Farmer_Nate]

I ruined an adjuster once. It was caused by me turning the screw when the bar wasn't really free. Loosening bar nuts on said saw was not enough. Try loosening bar nuts, wiggling the bar away from the saw to make sure it is clear of the saw, then adjust the screw slightly, then snug the nuts. The slot in my bar bound up on the bar studs. That was my issue, anyway.

You say your clutch cover bolts come off...hmm. Loose nuts put all the force directly on that adjustment screw. Sounds like the issue. Tighten, run, check nuts, run, check nuts...

 

[pdqdl]

In my experience, only two things will bend that bar tensioning assembly.
1. Not aligning the pin with the bar cover when assembling a chain & bar, and tightening it down. Common with rookies, but that doesn't quite look right to be the cause of your bent parts.
2, Banging the nose of the bar backwards, particularly if the bar cover is loose. This puts side torque on the pin, and it bends backward and the screw gets bent inward.

In light of the fact that you are reporting loose bar nuts at the same time, my guess is #2. Solution? Make sure your bar nuts are staying tight.

I think it is unlikely that engine horsepower alone is enough to bend the screw, but it's possible. When I am running a big bar on a saw, I often get the chain bound up in sawdust. This generally is solved by banging the top chain backwards on some log. Bad cases will get rougher treatment on the nose of the saw, all in an effort to free the chain without dismounting and clearing the chips.

If this has been happening to you, then that is where i would start looking for a solution. But otherwise, just keep those bar nuts tight.

 

[Maintenance supervisor]

I almost always tension the chain ,tighten the bar nuts then back the tensioner off . The clutch cover and bar nuts are what hold your chain tension not the tiny screw.
I used to bend the tensioner screw on my Promac700 when I'd get any kickback or roughly clear chips from the bar. Since I started backing the tension screw off the bar adjustment it doesn't happen.

 

[pdqdl]

...I'd get any kickback or roughly clear chips from the bar.

Yep. That's what I am talking about. Never heard the "backing the screw off" philosophy, but it sounds practical.

I've always considered that the chain wear will quickly "stretch" the tension into being loose again, so I don't worry about that too much. I get a lot of guys working for me that whine about how loose I allow the chain to run. "Don't you need to tighten that chain?", they will ask. I tell them "Nope. Just learn to keep the chain in the groove when you squeeze the throttle". I figure that running it a bit loose makes the chain and sprockets last longer. By contrast, over tightening the chain certainly wears them out faster.

Running a looser chain might well contribute to avoiding that bent tensioner. It will certainly reduce your chain & bar wear, but increase the number of times you throw a chain, at least until you learn how to avoid that problem.

 

[rahtreelimbs]

Yep. That's what I am talking about. Never heard the "backing the screw off" philosophy, but it sounds practical.

I've always considered that the chain wear will quickly "stretch" the tension into being loose again, so I don't worry about that too much. I get a lot of guys working for me that whine about how loose I allow the chain to run. "Don't you need to tighten that chain?", they will ask. I tell them "Nope. Just learn to keep the chain in the groove when you squeeze the throttle". I figure that running it a bit loose makes the chain and sprockets last longer. By contrast, over tightening the chain certainly wears them out faster.

Running a looser chain might well contribute to avoiding that bent tensioner. It will certainly reduce your chain & bar wear, but increase the number of times you throw a chain, at least until you learn how to avoid that problem.

Also running too tight over time is hard on the bearings too!

 

[martym14]

All great suggestions. I did make a bore cut with a lot of kickback going on. Maybe PDQDL’s second suggestion is what happened. The kickback caused the nuts to loosen slightly and there was a domino effect. I took it to an Echo only dealer this time, so I’m interested to see what they say.

 

[pdqdl]

Dealerships aren't necessarily manned by folks expert at using saws. Ask 'em how to avoid kickback during a bore cut, and watch for the blank look on their face while they try to figure out what you are asking.