Husqvarna 3120XP - Chain Locking Up

[internet.user.human]

Hello Chainsaw aficionados,

I recently got a secondhand 3120XP in basically new condition with no bar and chain included. I've been working on procuring a bar and chain for ripping with an alaskan mill and I ended up with an Oregon 363RNDD009 bar (3/8", 0.063", 115DL) and an Archer ripping chain with those same specs (I know, not the greatest chain).

I changed out my stock rim sprocket (0.404-7) with an Oregon 3/8-7 so I could use this bar and chain. That changeout process went over without any hitches that I know of.

Now when I finally got the bar and the chain in the mail and attached it to the saw, something isn't right. The chain spins freely when I just manually rotate it on the bar when it's off the powerhead, but once I put it on the saw. put the chain brake mechanism on, hand tighten the bar nuts, and then start to tension the chain with the screw, it seems to not tighten very easily. When I finally get to the point where the chain is just about flush with the bottom of the bar, the force to turn the tension screw seems too much.

Once I do have the chain tensioned correctly (I think - the chain is flush with the bottom of the bar at least), if I tighten the bar nuts down the chain won't move at all. I didn't realize this at first and tried cranking the saw; that's when I knew something wasn't right.

So, I'm attaching some photos from what I've observed after taking the brake assembly back off. I noticed that there appears to be some shearing or grinding on the shoulders of the chain brake frame, not sure when that happened but the paint is worn off and I can see a burr on the two spots. I'm also wondering if I correctly put this sprocket on. It can shift back and forth between the powerhead and the clutch drum when I move it with my finger, is that ok?

 

[J D]

Movement of the sprocket is normal, as is the wear on the cover.
Are you sure the chain drive links were in the sprocket correctly? If it was to one side that could cause the binding you're describing

 

[internet.user.human]

Movement of the sprocket is normal, as is the wear on the cover.
Are you sure the chain drive links were in the sprocket correctly? If it was to one side that could cause the binding you're describing

Yeah, before I fully tighten the bar nuts I can spin the chain (still hard with the 3120 compared to my 50cc poulan though!) but when I start to tension the chain and then tighten down the bar nuts, that’s when it’s stopping. It’s like the brake assembly is clamping the chain somehow but I can’t see where or why.

 

[buzz sawyer]

Is the clutch drum rubbing on the cover on those two spots? Is it the chain binding or the drum rubbing? Is the drum installed correctly?

 

[Fatherwheels]

Movement of the sprocket is normal, as is the wear on the cover.
Are you sure the chain drive links were in the sprocket correctly? If it was to one side that could cause the binding you're describing

Is the rim sprocket reversable, is on the correct side out.
Can you spin the clutch drum with your fingers with cover off,
I would not tighten the bar nuts much, also lift the point of the
bar upwards at the point and keep lifting until the tension of the
chain is right, then tighten the bar nuts, there is a lot of weight
in the bar and chain for the tensioner to lift on its own, it won't happen,
also be sure the chain is on the rim, it can easily get wedged if its not.

 

[BobL]

Have you tried assembling it without the clutch cover, use a couple of large washers - don't run it though.
The fact that it doesn't crank tells me something is jammed - you might be able to see where with the clutch cover off
You don't want the chain flushed hard with the bottom of the bar but about 1/32 or so below.
Once you get it going remember to adjust chain tension a few times in teh first few minutes of use when its new.

 

[internet.user.human]

Is the clutch drum rubbing on the cover on those two spots? Is it the chain binding or the drum rubbing? Is the drum installed correctly?

I was thinking that's what caused the paint to be worn away (drum rubbing) but I can't tell much when I get the brake assembly/cover on the saw.

 

[internet.user.human]

Is the rim sprocket reversable, is on the correct side out.
Can you spin the clutch drum with your fingers with cover off,
I would not tighten the bar nuts much, also lift the point of the
bar upwards at the point and keep lifting until the tension of the
chain is right, then tighten the bar nuts, there is a lot of weight
in the bar and chain for the tensioner to lift on its own, it won't happen,
also be sure the chain is on the rim, it can easily get wedged if its not.

I believe the rim sprocket is reversible; it doesn't look any different on one side than the other. I got this one: 3/8" - 7 Sprocket .

Now, when you ask if I can spin the clutch drum with my fingers when the cover is off, yes - but it's not freely spinning. I have to use a small amount of force to spin the clutch drum and get the piston to move. I assumed that was ok with this saw being so large and having the amount of compression it does. I was performing the steps as you said, only finger tightening the nuts, then lifting the bar nose up and pulling it to bring the chain close, then trying to tension it with the tension screw. I'm getting used to the much longer bar and chain so maybe I'm messing something up there. I can also see that the chain is on the rim so I don't think it's getting bound up there or not seating correctly.

 

[internet.user.human]

Have you tried assembling it without the clutch cover, use a couple of large washers - don't run it though.
The fact that it doesn't crank tells me something is jammed - you might be able to see where with the clutch cover off
You don't want the chain flushed hard with the bottom of the bar but about 1/32 or so below.
Once you get it going remember to adjust chain tension a few times in teh first few minutes of use when its new.

I have not done that yet, i'll try that so I can narrow down if it's the chain brake cover/assembly. Just slide on a few thicker washers on both bar studs to mimic the space taken up by the chain brake, and then finger tighten the bar nuts on to see if I can tension and spin the chain, correct?

 

[buzz sawyer]

Spinning the clutch drum with engine off should not move the crank and it should spin freely regardless of the engine size.
I'm still thinking the drum is not fully installed and sticking out. In the one pic, it looks like I see the roller bearing showing - doesn't look right.

 

[Aknutter]

How is the clutch drum engaging the oil pump gear? Is the clutch drum assembly correct?

 

[internet.user.human]

Spinning the clutch drum with engine off should not move the crank and it should spin freely regardless of the engine size.
I'm still thinking the drum is not fully installed and sticking out. In the one pic, it looks like I see the roller bearing showing - doesn't look right.

Nailed it Buzz.

Embarrassment on my part. When I replaced the sprocket I didn’t seat the clutch drum correctly when I put it back on and so it was sticking out farther than it should have been with the bearing visible. I fixed that, and once everything was back together the clutch drum spun freely. I placed the bar on the studs, chain on the bar, hand tightened bar nuts, tensioned the chain, (which still seems to take a lot of turning and tightening but it is a much larger bar than I’m used to) and then tightened the bar nuts down. Fired up on the second pull and works perfectly.

I knew after tinkering with it for a while that I’d find the answer here, so thanks for all your help everybody. I went from a poulan 50cc to this beast for milling so I’m still learning and adapting to the differences on this saw.

~J

 

[Husky77]

Hello Chainsaw aficionados,

I recently got a secondhand 3120XP in basically new condition with no bar and chain included. I've been working on procuring a bar and chain for ripping with an alaskan mill and I ended up with an Oregon 363RNDD009 bar (3/8", 0.063", 115DL) and an Archer ripping chain with those same specs (I know, not the greatest chain).

I changed out my stock rim sprocket (0.404-7) with an Oregon 3/8-7 so I could use this bar and chain. That changeout process went over without any hitches that I know of.

Now when I finally got the bar and the chain in the mail and attached it to the saw, something isn't right. The chain spins freely when I just manually rotate it on the bar when it's off the powerhead, but once I put it on the saw. put the chain brake mechanism on, hand tighten the bar nuts, and then start to tension the chain with the screw, it seems to not tighten very easily. When I finally get to the point where the chain is just about flush with the bottom of the bar, the force to turn the tension screw seems too much.

Once I do have the chain tensioned correctly (I think - the chain is flush with the bottom of the bar at least), if I tighten the bar nuts down the chain won't move at all. I didn't realize this at first and tried cranking the saw; that's when I knew something wasn't right.

So, I'm attaching some photos from what I've observed after taking the brake assembly back off. I noticed that there appears to be some shearing or grinding on the shoulders of the chain brake frame, not sure when that happened but the paint is worn off and I can see a burr on the two spots. I'm also wondering if I correctly put this sprocket on. It can shift back and forth between the powerhead and the clutch drum when I move it with my finger, is that ok?

Hello Chainsaw aficionados,

I recently got a secondhand 3120XP in basically new condition with no bar and chain included. I've been working on procuring a bar and chain for ripping with an alaskan mill and I ended up with an Oregon 363RNDD009 bar (3/8", 0.063", 115DL) and an Archer ripping chain with those same specs (I know, not the greatest chain).

I changed out my stock rim sprocket (0.404-7) with an Oregon 3/8-7 so I could use this bar and chain. That changeout process went over without any hitches that I know of.

Now when I finally got the bar and the chain in the mail and attached it to the saw, something isn't right. The chain spins freely when I just manually rotate it on the bar when it's off the powerhead, but once I put it on the saw. put the chain brake mechanism on, hand tighten the bar nuts, and then start to tension the chain with the screw, it seems to not tighten very easily. When I finally get to the point where the chain is just about flush with the bottom of the bar, the force to turn the tension screw seems too much.

Once I do have the chain tensioned correctly (I think - the chain is flush with the bottom of the bar at least), if I tighten the bar nuts down the chain won't move at all. I didn't realize this at first and tried cranking the saw; that's when I knew something wasn't right.

So, I'm attaching some photos from what I've observed after taking the brake assembly back off. I noticed that there appears to be some shearing or grinding on the shoulders of the chain brake frame, not sure when that happened but the paint is worn off and I can see a burr on the two spots. I'm also wondering if I correctly put this sprocket on. It can shift back and forth between the powerhead and the clutch drum when I move it with my finger, is that ok?

The last pic of your sprocket, thats the problem, not seating!

 

[Woodslasher]

Hello Chainsaw aficionados,

I recently got a secondhand 3120XP in basically new condition with no bar and chain included. I've been working on procuring a bar and chain for ripping with an alaskan mill and I ended up with an Oregon 363RNDD009 bar (3/8", 0.063", 115DL) and an Archer ripping chain with those same specs (I know, not the greatest chain).

I changed out my stock rim sprocket (0.404-7) with an Oregon 3/8-7 so I could use this bar and chain. That changeout process went over without any hitches that I know of.

Now when I finally got the bar and the chain in the mail and attached it to the saw, something isn't right. The chain spins freely when I just manually rotate it on the bar when it's off the powerhead, but once I put it on the saw. put the chain brake mechanism on, hand tighten the bar nuts, and then start to tension the chain with the screw, it seems to not tighten very easily. When I finally get to the point where the chain is just about flush with the bottom of the bar, the force to turn the tension screw seems too much.

Once I do have the chain tensioned correctly (I think - the chain is flush with the bottom of the bar at least), if I tighten the bar nuts down the chain won't move at all. I didn't realize this at first and tried cranking the saw; that's when I knew something wasn't right.

So, I'm attaching some photos from what I've observed after taking the brake assembly back off. I noticed that there appears to be some shearing or grinding on the shoulders of the chain brake frame, not sure when that happened but the paint is worn off and I can see a burr on the two spots. I'm also wondering if I correctly put this sprocket on. It can shift back and forth between the powerhead and the clutch drum when I move it with my finger, is that ok?

The last pic of your sprocket, thats the problem, not seating!

Bingo, the teeth in the clutch drum need to align with the notches in the oiler gear, and yours do not. Aligning them should fix your problem.

 

[BetzyF4ever]

Bingo, the teeth in the clutch drum need to align with the notches in the oiler gear, and yours do not. Aligning them should fix your problem.

Now this awesome advice deserves a photo assist??