Has anyone ever seen a stock MS250 or any stock stihl with 190psi of compression? The saw is about 2 years old, light use. The piston and rings are very shiney. No carbon on top or on roof of cylinder. The exhaust is black but no build up. The exhaust side of the piston is a warm gold. Stihl oil has been used. The owner is complaining of hard to pull start. The saw runs and starts great. Is it possable an incorrect piston could have been installed? If it is I would love to put one in all my 250's!!! Thanks for any assistance.