McPherson
ArboristSite Member
Hi folks,
Been long time since I went here, was pretty busy and now 2 kids (2 years old and 1 month old).
Just bought a second saw for limber (572XP), so far loving it!
My smaller saw (550XP, MY 2012 with about 40 hours of use) had some hot start issues so I did a compression test, the reading was 90 psi. Damn.
Decided to open to case to see what's going on.
Intake side
https://photos.app.goo.gl/6J7FYJ2cGZmQvhpZ6
Exhaust side
https://photos.app.goo.gl/KaY7FJyaxnS4nGbJA
Cylinder bore
https://photos.app.goo.gl/FBEtiWGJnAaE6cFG8
No alum transfer on the cylinder walls. Ring end gap 0,013" above the exhaust port, 0,015" in center and under. Can see some blowby on the piston under the ring. Can still see machining cross-marks on the bore.
So, what should I do? Change piston and ring? Ring only? Change nothing, put it back and beat the hell out of it? What could cause the blowby and the poor compression?
Will do a pressure test too to check the crank seals, probably change them anyway since the saw is already in pieces.
Thanks for the help!
Francis
Been long time since I went here, was pretty busy and now 2 kids (2 years old and 1 month old).
Just bought a second saw for limber (572XP), so far loving it!
My smaller saw (550XP, MY 2012 with about 40 hours of use) had some hot start issues so I did a compression test, the reading was 90 psi. Damn.
Decided to open to case to see what's going on.
Intake side
https://photos.app.goo.gl/6J7FYJ2cGZmQvhpZ6
Exhaust side
https://photos.app.goo.gl/KaY7FJyaxnS4nGbJA
Cylinder bore
https://photos.app.goo.gl/FBEtiWGJnAaE6cFG8
No alum transfer on the cylinder walls. Ring end gap 0,013" above the exhaust port, 0,015" in center and under. Can see some blowby on the piston under the ring. Can still see machining cross-marks on the bore.
So, what should I do? Change piston and ring? Ring only? Change nothing, put it back and beat the hell out of it? What could cause the blowby and the poor compression?
Will do a pressure test too to check the crank seals, probably change them anyway since the saw is already in pieces.
Thanks for the help!
Francis