I have an older Snapper 32" walk behind model W32080 from around 1987. When I start the motor it will idle fine in neutral, but when I release the control levers to engage the drive it dies a few seconds later. The manual says to release the levers to engage the drive, but surely they don't mean to release them all the way to where the interlock plungers are completely retracted. The plungers are adjusted as far out as possible. Do I just need to adjust the drive so it engages sooner? Also I have an oil leak at the base of the engine, and white smoke out the carb when the motor is shut down. I also get a surging at idle sometimes because the choke plate and linkage are moving back and forth. It's an 8hp Briggs. I don't think it had these problems when I took it out of the shop but I just took it on a bouncy 1000 mile road trip so I'm thinking something could have been knocked loose. Thanks for any help!