problems with my 01 mercury 20hp

hey guys i need some help...ive taken my boat out before a couple times and the last time i took it out the motor ran fine but i noticed a very bad gas smell and also got a really bad headache. i got home and come to find out my gas lines were slit. so i changed fule lines and connections from the motor and the gas tank. put new gas/oil mixture in and my engine doesnt start. i took the carb off and soaked it in carb cleaner,checked the spark plugs and still nothing. ive done everything but change the gas,i got my gas from a different place last time than the times before...is there any other ideas that i can do before i take it to a marine mechanic?
thanks
Jay

Make sure you have spark,than take a little gas-oil mixture & squirt in the carb & see if it starts.

If it ran before it is probably something simple.

We''ll go from there.

Does your motor have a dead man switch?

thanks for the replies. i will try and do this tmrw and will let you know what happens...
the motor has an off-on switch and i did remember to turn it on

new gas mixture and nothing...had to take it in today....and they actually were able to start on it today. should b out by the time the rain stops, good thing i have tax return coming in

Plugs may have been fouled if you had bad gas or water in it. Hope they get it going.

yea thats what i thought also... the called me today to say the boat is finished and everything is working again.had the carb fully rebuilt apparently some needles were really clogged up..so as soon as the tax return comes in im goin to pick it up. thanks for the replies guys
Jay