550xp: throttle return and sprocket spin

[kyle1!]

I have a couple of problems with my 550xp. I know one fix is probably easy but the other has me concerned.

First the throttle does not return very easy so to get the saw to slow down I have to use my fingers to pull the trigger back out of the handle. Does the cable need some lube or is there other issues?

2nd problem that has me concerned is a spinning sprocket. I was using the saw yesterday in a log and the chain just stopped moving on the bar in the cut. Upon inspection the sprocket can spin freely. Is there a drum with clip that holds the rim sprocket in place? I didn't think outboard clutches had such a setup so did I strip the sprocket or crank?

Thanks. Brian

 

[Huntaholic]

Something is causing your throttle to hang, have you broke or bent the housing? theres not much else I can think of that would cause that issue. As to the chain spinning on the sprocket, its possible the rim broke in half. They will do that if ran too long. Its either that or you have stripped the splines off the drum. My money is on a broken rim sprocket though.

 

[Franny K]

Do you describe a rim sprocket spinning while the clutch drum is stationary? I believe the splines are oven brazed or soldered to the drum.

The sprocket is splined to the drum with the piece that drives the bar oiling on the inside. The center of the centrifugal clutch threads to the crankshaft to hold things together.

Issue 1 happens when saw gets squashed as suggested above. Could be debris wedged, has it been stuffed in brush pile?

 

[kyle1!]

The rim sprocket spins like it is no longer on a splined drum with or without the saw running. Was not sure if there was a C clip holding the rim onto a drum and I lost it while cutting.

Saw has not been squashed or bent as far as I know. I use it to cut brush/small seedlings sometimes. It is my saw for wood under 12inches. I need to take it apart and see. Always come to AS 1st so I can be pointed in the right direction.

 

[Andyshine77]

The 550 has an outboard clutch, no clip, the drum is held on by the clutch. Time to remove the clutch and inspect.

 

[kyle1!]

I see in other messages that to remove the clutch I need to use a punch to hit the clutch in the off direction. Is there some trick to it? When I hit all it does is spin. From what I could see the drum/spline have separated

 

[Andyshine77]

The clutch will spin off, it take a good smack. I however made a tool out of a socket that fits over the clutch. crude but effective.

 

[Huskitoter]

Like mentioned above, you can't tap it off. It takes a forceful blow to break it loose. Rotate the shaft around with your pull chord to where the compression will hold it before hitting it.

Some people remove the spark plug and use a piston stop to keep the shaft from turning (nylon rope works good). Probably a bunch of vids on YouTube showing how to do it.

 

[kyle1!]

Finally getting back to the saw. The throttle trigger has about 1/8 to 1/4 of its travel still to go once I let off when cutting. My plan in to replace the throttle cable and check the springs. But first I must get the pin out that is holding the trigger. Does this push out moving from left to right? My few taps with a hammer and small allen wrench did not yield any movement. I am working out in the cold garage and did not want to break the handle etc.