G'day Mate,
What size prop are you using? It may be 4 time bigger than your last engine, but it will not have a prop that is 4 times bigger, start with a 12x6.
As was previously stated, it may be flooded, but the best idea is to take it to a club field, & get help, if you don't know how to start an engine, I'm thinking you also don't know how to fly!!!