Jump to content

Log in or register to remove this advert

What's on your bench today?


spudulike

Recommended Posts

:lol::lol::lol:

as always spud u have a pic for everything and great at explaining things :thumbup:

 

Thanks Martin,

Re the problem, get a photo up, you can get some strange effects that I put down to the flow of exhaust gases and the way the earth electrode gets in the way of them!

Link to comment
Share on other sites

Log in or register to remove this advert

Using an MS240 on saturday, I had set saw down to move some brash when I heard a rattle from engine just for a second then the saw stopped. I tried to pull the started cord gently but saw would not turn over. On inspection the top section of the piston was broken along with the top ring just opposite the exhaust port.

 

Looking closely at the piston after removal, the top compression ring has turned past the retaining post in the groove right round so that the gap in the ring was opposite the exhaust port, where it obviously has caught the port and as a result broke the piston and ring.

I believe the pin which prevents the ring from turning in the groove has worked loose and worn both pin and the hole it locates in enough to let the ring turn. This saw was rebuilt 3 months ago including bearings seals gaskets and a GOLF piston kit. Was this a faulty piston or did I do something wrong. Locating pins were at the intake side and rings were gapped in the bore before fitting. It was in the original cylinder which was sanded clean to remove previous alloy transfer marks. Cylinder looks fine still apart from a small burr on the exhaust port obviously damaged when the ring broke.

 

Photos

IMG_0817_zps985675b2.jpg

 

IMG_0819_zps3da90b11.jpg

 

IMG_0820_zpsf15279e3.jpg

Link to comment
Share on other sites

Using an MS240 on saturday, I had set saw down to move some brash when I heard a rattle from engine just for a second then the saw stopped. I tried to pull the started cord gently but saw would not turn over. On inspection the top section of the piston was broken along with the top ring just opposite the exhaust port.

 

Looking closely at the piston after removal, the top compression ring has turned past the retaining post in the groove right round so that the gap in the ring was opposite the exhaust port, where it obviously has caught the port and as a result broke the piston and ring.

I believe the pin which prevents the ring from turning in the groove has worked loose and worn both pin and the hole it locates in enough to let the ring turn. This saw was rebuilt 3 months ago including bearings seals gaskets and a GOLF piston kit. Was this a faulty piston or did I do something wrong. Locating pins were at the intake side and rings were gapped in the bore before fitting. It was in the original cylinder which was sanded clean to remove previous alloy transfer marks. Cylinder looks fine still apart from a small burr on the exhaust port obviously damaged when the ring broke.

 

Photos

IMG_0817_zps985675b2.jpg

 

IMG_0819_zps3da90b11.jpg

 

IMG_0820_zpsf15279e3.jpg

 

Probably just a faulty piston with a loose location pin, it does happen even on OEM pistons - Golf are generally not a bad choice piston - better than many!

Link to comment
Share on other sites

The pot is actually fine apart from a small burr on the exhaust port where the ring must have caught. I think the fact the saw was at idle when it happened really reduced damage to a minimum. I would hope to have it going again by Wednesday. I cant be without it at the minute

 

EDIT should I try the supplier for a replacement free of charge. Think it came from GHS.

Link to comment
Share on other sites

EDIT should I try the supplier for a replacement free of charge. Think it came from GHS.

 

I would, particularly if you can find the receipt or other proof of purchase (even electronic). You at least want to be sure where you got it so you aren't getting 'free' parts from the wrong supplier.:001_smile:

 

I believe GHS offer a 1yr warranty and your photos prove it wasn't lean seized through a fuel issue. I would ring them up, explain what happened and offer to email them the photos. My guess is they will send you a replacement FOC by return.

 

Alec

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  •  

  • Featured Adverts

About

Arbtalk.co.uk is a hub for the arboriculture industry in the UK.  
If you're just starting out and you need business, equipment, tech or training support you're in the right place.  If you've done it, made it, got a van load of oily t-shirts and have decided to give something back by sharing your knowledge or wisdom,  then you're welcome too.
If you would like to contribute to making this industry more effective and safe then welcome.
Just like a living tree, it'll always be a work in progress.
Please have a look around, sign up, share and contribute the best you have.

See you inside.

The Arbtalk Team

Follow us

Articles

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.