Got a snow blower but it doesn't run.I got nowhere to work on it.I get spark but won't fire.Was told by a repair guy that I needed to rebuild it because it had no compression.Am i wrong,if it had spark and it had gas would it not at least fire? He says it won't run because of the low compression,about 20 psi i think he said.Supposed to be 50 psi.I want to take the carb off but nowhere to do it.I got lots of shovels.Funny thing is 2 winters ago it ran fine,wasn't used last winter,gas is ok.