Hey guys. I have a 2000 model 250 trailblazer. Got it from a guy because he was having carb trouble. Tured out to just be a piece of trash in the main jet, it has been running fine since. Was parked for 4 years. Last time i rode everything seemed fine untill i pulled down a hill and tried to back up. I hit the gas and it just bogged down. Tried a couple times and nothing. Was ideling fine by the way. Got off made sure oil was getting to it. Was smoking like normal. Motor didn’t feel hot. Got on and tried again and bogged down and back fired through carb it sounded like and hasn’t started since. Compression still feels good on pull. I suspect crank seals but do not have acusses to a leakdown tester so was wondering what yall thought or if had ever had similar problems. It sounds like it is pulling alot of air when i pull it. Thank you