postmortem for my string trimmer

[WalterWhite]

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

 

[Fish]

To get any warranty, you need proof of purchase, time, store, etc....
Yes, the failure looks like a bearing failure, not your fault...

 

[robertjinnes]

ryobi 33cc

Are you also missing a piece of the top piston ring? It may correspond to the piston and cylinder gouge. Possibly 2 unrelated failures. With bearing gone, compression will be way down since you can't drive the piston to normal squish. Stuck ring or rings also hurts compression. I would contest ryoby's findings. Give them honest info on # of tanks, oil mix ratio etc. Try to get them to cough up a Return Material Authorization. Shipping for that may be free. I've got a similar machine and earlier this month pried out the limiters so I could get it to run like it should. Now it runs correctly. Before the adjustment, running it over ACCIDENTLY OVER AND OVER was seeming to be the right thing to do. Good luck

 

[Fish]

Depending on the store where bought, you have differing options.

 

[chainsawland]

I have never liked IDC / Ryobi trimmers, but that takes the cake.

 

[WalterWhite]

Thanks for the replies folks.

To get any warranty, you need proof of purchase, time, store, etc....
Yes, the failure looks like a bearing failure, not your fault...

I have all that.

Are you also missing a piece of the top piston ring? It may correspond to the piston and cylinder gouge. Possibly 2 unrelated failures. With bearing gone, compression will be way down since you can't drive the piston to normal squish. ...

The compression ring is all there. It is stuck where the piston was gouged. You are absolutely right about the loss of compression due to reduced piston travel. I think that is probably the main cause of loss of compression and the gouge in piston and compression ring just contributes.

Depending on the store where bought, you have differing options.

CPORyobi.com In fact, I found it as a result of the reports of a refurb Ryobi chain saw that was talked about here about a year ago. I hope the folks who bought the chain saw are having better luck. CPO just refers customers to Ryobi for warranty and that actually seems to get me to Homelite.

And yes, honesty about this is the best policy. But there is nothing to hide. I warm it up before use, cool down before stopping it and use the proper mix so there is nothing to hide.

I've submitted a description and pictures to their web site to see what they say. At worst, I can buy a P&C and gaskets for about $50. unless someone can suggest a better supplier than http://www.ereplacementparts.com/ry...and-brushcutter-parts-c-7931_15633_15693.html

thanks,
walt

 

[indiansprings]

Buy yourself a Stihl 90R and life will be good again. You can add a chainsaw attachment to them as well.