Stihl chain keeps coming loose

[Deleted member 168049]

Video of Chain tension and rubbing
Chain oiler

Sorry about my manky fingers

 

[SteveSr]

Is the pitch on that chain correct? It doesn't look like a Stihl chain.

Also looks like you have a running issue. Couild be fuel/carb or wonky ignition. Acts like it is firing every couple of revolutions.

 

[Deleted member 168049]

Is the pitch on that chain correct? It doesn't look like a Stihl chain.

Also looks like you have a running issue. Couild be fuel/carb or wonky ignition. Acts like it is firing every couple of revolutions.

Yep, 3/8"

 

[SteveSr]

Yep, 3/8"

Next thing to try is a brand new chain. This will rule in/out damaged (peened) drive links which happens from running on a worn out sprocket. It also looks like you could add the second bar stud to that case (although you really shouldn't have to). You may have to drill out / or replace the clutch cover.

Also you should see oil dribbling out the oil feed hole when you run the saw like your video. I couldn't tell from your video. Obviously the bar has to sit flush and tight to the case to get the oil into the bar feed hole.

 

[Deleted member 168049]

Next thing to try is a brand new chain. This will rule in/out damaged (peened) drive links which happens from running on a worn out sprocket. It also looks like you could add the second bar stud to that case. You may have to drill out / or replace the clutch cover.

I've got 2 brand new chains and get the same issue with both. Might be time to sell the saw, this is becoming rather wearing

 

[SteveSr]

I've got 2 brand new chains and get the same issue with both. Might be time to sell the saw, this is becoming rather wearing

What brand are these brand new chains. If they have both been run on the old sprocket they may both be damaged now. Clean up the chains with solvent and then carefully examine the drive links for hammering damage where they contact the sprocket.

Alternatively if you have a good caliper check the thickness of the drive surface on the drive link to rest of the drive link. Should be less than .050"... the width of the bar groove. If you have feeler gauges you can also verify that there are no tight spots in the bar groove.

Final thought... what kind of shape is the clutch bearing in? These have plastic carriers and can melt and deform under abusive conditions.