Does this engine issue sound serious / expensive?

[rusticles]

I have a DF2.5 which I've had regularly serviced from new in 2006 and it has only been used lightly. A few weeks ago I noticed it would idle properly and I kept having to give it a little throttle to keep it going. I reported this to a suzuki dealer when I took it in for its annual service and after the service they said that they had cleaned out the carburettor as there has been some deposits in there and they said they had increased the idle speed slightly. The next time I used it there was no issue but, then the next time it kept trying to cut out again, and I had to give it more and more throttle to keep it going, even at higher engine speeds. Today I tried to start it and I couldn't pull the starter cord as there was so much resistance. I left it half an hour, and tried again, when it started ok. But I noticed that there was a lot of smoke and the bucket of water I ran it in became very oily (maybe it was oil or fuel) and although it ran I kept having to increase the throttle. Also, I don't know if I'mn imagining it but the leg seemed to be quite hot - but maybe this is normal and I just haven't noticed it before. I will definitely take it in to be looked at but can anyone give any likely causes. Is this going to be an expensive problem. Any help would be much appreciated.
Many thanks,
Paul

[mitch]

Is that motor still under warranty they have 5 years in oz ?

[rusticles]

When I bought this one, they only had 3 yrs warranty, so no unfortunately not! The new ones now have 5 years though I believe.

[boats.net]

If the motor is removed from boat and stored on side then make sure is not laying on wrong side as oil will fill cylinder full of oil. If carb floods then gas will flood cylinder and prevent engine from turning over and will fill oil pan with gas, check oil to see if smells like gas.