WalterWhite
ArboristSite Member
Technically off topic... But it does have a chain saw attachment. :greenchainsaw: I don't know of another site with the conmbined knowledge of the membership here. (Where's the emoticon fur suck up when I need it. )
My string trimmer died earlier this week. I was operating it and it just shut down. It stopped like I flipped a switch. No slow down or other symptoms - just stopped Right Now. When I pulled to start it, I was disappointed to find that it pulled a whole lot easier than when I started it a few minutes earlier. History is that I purchased this (Ryobi bush trimmer with 30cc engine, reconditioned unit.) last August. I've probably run about 5 tanks of fuel through it.
Due to the abrupt shutdown, I suspected a catastrophic failure. The first thing I noticed was a scored piston:
Further inspection showed a problem between the wrist pin and con-rod:
In fact, the connection is so loose:
:jawdrop:
There's also gouging at the crank end of the con-rod where debris got caught between the rod and crank case.
While taking pictures, this part fell out of the piston:
You can also see a gouge in the piston skirt that matches a corresponding gouge in the cylinder wall.
It appears to me that a failure of the bearing or bushing between the wrist pin and con-rod released debris that damaged the compression ring resulting in a sudden loss of compression. What would have caused that?
I should mention that I have an agenda here. I took this to an authorized Ryobi service center and they diagnosed worn piston rings which resulted in a warranty decline. Worse yet, they charged me $35 for the diagnosis which is IMO in error. (I plan to contest the charge.)
I appreciate your thoughts on what caused the wrist-pin to con-rod connection to fail.
thanks,
walt
My string trimmer died earlier this week. I was operating it and it just shut down. It stopped like I flipped a switch. No slow down or other symptoms - just stopped Right Now. When I pulled to start it, I was disappointed to find that it pulled a whole lot easier than when I started it a few minutes earlier. History is that I purchased this (Ryobi bush trimmer with 30cc engine, reconditioned unit.) last August. I've probably run about 5 tanks of fuel through it.
Due to the abrupt shutdown, I suspected a catastrophic failure. The first thing I noticed was a scored piston:
Further inspection showed a problem between the wrist pin and con-rod:
In fact, the connection is so loose:
There's also gouging at the crank end of the con-rod where debris got caught between the rod and crank case.
While taking pictures, this part fell out of the piston:
You can also see a gouge in the piston skirt that matches a corresponding gouge in the cylinder wall.
It appears to me that a failure of the bearing or bushing between the wrist pin and con-rod released debris that damaged the compression ring resulting in a sudden loss of compression. What would have caused that?
I should mention that I have an agenda here. I took this to an authorized Ryobi service center and they diagnosed worn piston rings which resulted in a warranty decline. Worse yet, they charged me $35 for the diagnosis which is IMO in error. (I plan to contest the charge.)
I appreciate your thoughts on what caused the wrist-pin to con-rod connection to fail.
thanks,
walt