My daughter's PW50 started getting hard to start, but would it fire right up with a little shot of ether, and then ran fine after that. I checked the compression and it was down around 90 psi, so I put a new topend on it (including new cylinder and head) last week, but it is still acting exactly the same. I've cleaned the carb twice, and it has a brand new air filter and coil on it. Spark is strong and plug is a nice tan color. I pulled the flywheel off last night, and the crank seal looks okay. I'm planning on checking the reeds tonight. Any other ideas? I don't understand why it would run great but not want to start.