I just had a machine in use on friday. The guys called me and said it ran out of gas. they fueled it up and it wouldn't go. I asked if it was bone dry. they said only a small amount on bottom of tank. I figured it needed a prime or something. We put fuel in the carb intake, got no response. Checked for spark, all was well. Checked compression, 25psi. Uh Oh. Not just out of gas. So I pulled the valve cover and turned over motor, I could tell by the sound that it had no real pressure there. I noticed the push rods were not moving as the engine turned over. Is this a bad cam or something. Ideas would be helpful. Thanks.