Chainsaw Repair

Husqvarna - Stihl - Poulan - Jonsered - Dolmar chainsaws and more => Stihl => Topic started by: Sintersis on October 14, 2013, 01:59:14 pm

Title: 038 piston question
Post by: Sintersis on October 14, 2013, 01:59:14 pm
Hi all, new member here
I have a second hand stihl 038 that won't start, I've been through the usual suspects with the ignition and fuel/carb side of things
I've also checked the carb to cylinder hose/sleeve and the impulse hose that's hiding back there but still nothing

As a last resort I pulled the cylinder head off to check as I noticed some scratches on the piston and found this

(http://i57.photobucket.com/albums/g219/sintersis/photo.jpg) (http://s57.photobucket.com/user/sintersis/media/photo.jpg.html)
(http://i57.photobucket.com/albums/g219/sintersis/photo-3.jpg) (http://s57.photobucket.com/user/sintersis/media/photo-3.jpg.html)

In the collective oppinions of the forum is this piston shot ??
Title: Re: 038 piston question
Post by: Cut4fun on October 14, 2013, 02:15:13 pm
Welcome.

On PB pics use IMG code to embed like this.

(http://i57.photobucket.com/albums/g219/sintersis/photo.jpg) (http://s57.photobucket.com/user/sintersis/media/photo.jpg.html)
(http://i57.photobucket.com/albums/g219/sintersis/photo-1.jpg) (http://s57.photobucket.com/user/sintersis/media/photo-1.jpg.html)
Title: Re: 038 piston question
Post by: Cut4fun on October 14, 2013, 02:16:10 pm
That one looks shot.

Check to see if you can save the cylinder.
Title: Re: 038 piston question
Post by: Sintersis on October 14, 2013, 04:25:49 pm
Here's a few pics of the cylinder, It has some finer scratches but i guess that the pot is chrome lined and the piston is soft aluminium or magnesium and designed to wear ??

(http://i57.photobucket.com/albums/g219/sintersis/IMG_1027.jpg)

 (http://s57.photobucket.com/user/sintersis/media/IMG_1027.jpg.html)(http://i57.photobucket.com/albums/g219/sintersis/IMG_1023.jpg) (http://s57.photobucket.com/user/sintersis/media/IMG_1023.jpg.html)

what ever the outcome I'm preparred to buy a piston and pot if it's necessary, just to get the saw running and useable.
Title: Re: 038 piston question
Post by: Fish on October 14, 2013, 06:17:23 pm
looks like straight gas....
Title: Re: 038 piston question
Post by: Bitburger on October 14, 2013, 06:32:16 pm
you might be able to save the cylinder, but you have to remove ALL of the depositions that came from the piston!

When you re done, you can check if the chrome (or Nikasil) is still okay. It will also get worn off when removing the aluminum, this is why you can't tell before.

Some fellows at home now switched to sodium hydroxide to remove the aluminum chemically. I am not convinced but give him a try !
And always where protective glasses!!!
Title: Re: 038 piston question
Post by: Al Smith on October 16, 2013, 04:50:13 pm
Probabley the safest way to get rid of the tramp aluminum is with a Scotch -Brite pad using kerosine,diesel fuel or WD-40 . Don't get in a hurry and try honing it out .Take it from one who knows a hone will go right through the plating .

That piston is shot no doubt .