cedarshark
Addicted to ArboristSite
Good morning. I have a MS390 that locked up in the cut last fall. I finished the job with my 044 and set the 390 on the bench, afraid to take my first crack at messing with a major clamshell repair. I got tired of it staring at me and, on disassembly, I discovered a small ball bearing from the compression release lodged under the crank. The ball bearing pinged the top of the piston a couple of times and the bottom of the pan but did not get into the bearings or do any damage to the sides of the piston or cylinder. The bearings rotate smoothly.
1) I cannot locate the compression release pin. I guess the saw dispelled it out the top. I plan to plug the compression release with a bolt.
2) My plan is to replace the seals, clean the ring grooves and re-use all orig parts. The piston shows light wear wear but the skirts still show machining marks, so I believe it is good to go.
3) The engine has been removed from the saw and I would like to re-install the same way if possible. When the engine was removed, the Dirko sealant held the pan on the cylinder. Can I apply Dirko the pan, clamp the pan to the cylinder,let it dry, the reinstall in the case, or do the bolts that hold the engine to the case provide the necessary torque to seal the pan to the cylinder ? I guess (in summary)I am confused about the order of the engine reassembly back into the frame.
4) Is there something else that I could be missing? I can post pics of the damage to the piston top but it's not very dramatic !
Thanks for the help.
1) I cannot locate the compression release pin. I guess the saw dispelled it out the top. I plan to plug the compression release with a bolt.
2) My plan is to replace the seals, clean the ring grooves and re-use all orig parts. The piston shows light wear wear but the skirts still show machining marks, so I believe it is good to go.
3) The engine has been removed from the saw and I would like to re-install the same way if possible. When the engine was removed, the Dirko sealant held the pan on the cylinder. Can I apply Dirko the pan, clamp the pan to the cylinder,let it dry, the reinstall in the case, or do the bolts that hold the engine to the case provide the necessary torque to seal the pan to the cylinder ? I guess (in summary)I am confused about the order of the engine reassembly back into the frame.
4) Is there something else that I could be missing? I can post pics of the damage to the piston top but it's not very dramatic !
Thanks for the help.