ran fine for the first 3 months i had it then developed a loping idle .... and its not a air leak.
i suspect damaged valve seats on mine.
yours ... having the fuel odor i suspect over rich and under timed as u say ur spark is retard quite a bit, so i expect exsess fuel vapour. Not sure on the 2tg but if u run a charcoal canister it could be that it is blocked and the vapours are thereby escaping to the engine bay... then into ur vents?