1887 ski doo escapade won't start

Hi I recently bought a 1987 ski doo escapade off criegslist for 350 it's in great shape and only rust under the hood is on the exhaust pipe the electric start was shot so the previous owner fired it up and drove it right on to the trailer. Upon takeing it home I manually started the sled in my garage with same result started up fine the exhaust was pretty thick though so I'm not sure if it's just a combination of the age of sled and the fact it's been sitting all summer. I turned the sled off for the night and in the morning I purchased a brand new battery for the electric start I installed it and tried to start it up.The sleds engine sounds like it's about to roll over but just doesn't get there so I thought Maybe something was still wrong so I tried to manually start and it didnt work either! The spark plugs were looking black so I replaced those last night but alas no difference sled refused to start. I'll take some sled shots when I get home

1887 ski doo escapade won't start