JD X300 w/360 hrs - Smoke from exhaust, possibly not running at full power?

Last week the X300 was running fine, this week it just didn't seem like it was running right. It "seemed" like there was a miss or something on low idle but when I powered up the motor and engaged the blades it seemed to cut ok but I "felt" that it didn't have the power that it had previously and even though it is windy here today, I could catch a whiff of gasoline periodically. I stopped the mower, and checked the fuel line to make sure there were no leaks. I also checked the dipstick and indicated it was full. I don't have a great nose but it did smell a bit like gasoline but nothing strong. I was a bit worried because I just didn't feel it was running right so I would stop every now and then and let it sit to cool off. I was almost through mowing when it started to puff what looks like a little bit of smoke out of the muffler. My nephew asked that I drain a bit of oil out into a can and he's going to look at it for me tomorrow. The oil isn't very dirty but does have a faint gas smell. I would appreciate your opinions as to what might be happening. If you need more information, I'll try to provide it. I would really appreciate some help. I'm worried that the engine is blowing up or something, which I can't believe because the mower isn't all that old.



Thank you,



Carolyn