Yamaha 200hp year 2000 won't idle

[Lovetoboat]

End of last season was cruising fine when came into harbor and as I idled down it kept stalling in idle. Over the winter I replaced the plugs, fuel filter, etc. Back in the water now, when it first starts it's fine for a minute or two then it continues to stall in idle. Also, blue smoke while idleing, in gear running at 1200rpm and above it runs fine, no smoke.

Thanks
Tom