Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: scot_91 on July 23, 2018, 09:10:50 pm

Title: Stihl 064 av
Post by: scot_91 on July 23, 2018, 09:10:50 pm
Im new to the forum. I have a question about my Stihl 064 av chain saw. I bought this saw at a yard sale for $20 the people said they didnt know whats wrong with it. I brought it home tried to pull it over and it was locked up. I pulled the cylinder off and seen that the piston was broke on the carburetor side. I found some big pieces of the piston down inside. I got them out and it rolled over. the cylinder looks fine. My question is what made the piston break like that. Ill try to figure out how to post pictures of the piston so everyone can see. Thanks for any help!
Title: Re: Stihl 064 av
Post by: scot_91 on July 24, 2018, 02:06:11 am
This is what the Piston looks like.
Title: Re: Stihl 064 av
Post by: scot_91 on July 28, 2018, 08:11:46 pm
Here is another picture
Title: Re: Stihl 064 av
Post by: trappermike on December 29, 2018, 05:01:06 pm
Usually when in a chainsaw you find that the piston's intake skirt has shattered most times I found the cause to be that the intake skirt had gotten so worn that it finally gets so thin and weak that it will eventually shatter and leave lots of debris in the crankcase. This is almost always due to the saw have a poor air filter and sucking in lotsa dirt,which goes down the intake port and hits the intake skirt,wearing it away until it breaks,a few models were famous for that,Mag2 and earlyist 064's.
Usually the cylinder is ok,you just need to wash out the crankcase very well(filling it with fuel mix,spinning the crank around,then quickly flipping the saws and dumping it out,repeat until the fuel in the crankcase is clean) Then look closely for anywhere all that dirt was getting into the crankcase and fix it,often just a bad filter or not sealing well.
In a rare occasion something has gone down the intake port(like a loose throttle plate screw or something like that. The picture of your piston almost looks like maybe something got sucked in,check all those possibilities before running it again.