If you have raw gas coming from your exhaust, you have issues. If you have a plug fouled or for what ever reason not firing would allow this. Check your spark on all cylinders. IF you lack spark at one or the other, then you problem lies most likely in your cap, button or wires. If you have good fire on all of them, then it's a plug issue, or a really bad valve and or seat issue. Another cause could be your carb. If the float is hung up or way out of adjustment, it could be sending a lot of fuel. You should see a lot of black smoke if it is. Do a tune up, cap, rotor button, wires and plugs. At the same time, change the oil. If that much gas is getting by, then you may have washed down some cylinder walls. I would add a can of restore to it too.
While we are on your subject, are you sure it's gas? could be condensation too. Feel and smell of it and see.
As far as the lift, we don't know you or your skill level. If you doubt yourself, have a friend who has done this to help, or take it to a reputable shop.