Very few hours, but set for 8 months, now won't start.  

We need a few more details before we can even START to help you.  

1.  Engine cranking/turning over?  If yes, go to 2. If not, check battery--charge and try again.

2.  Getting spark to plug? If yes, go to 3. If no, you have an electrical problem with the ignition.  Suspect coil or stator. Do you know how to check this?  If not, locate the spark plug and remove boot from plug.  Put screwdriver in spark plug boot and hold so that metal of screwdriver is about 1/4" from engine head.  Crank engine.  You should see bright blue spark go from screwdriver to head.  Hold screwdriver by plastic handle and do not touch metal of screwdriver when you do this or you might get a shock--this is not a dangerous procedure unless you have an open container of inflammable material nearby.

3. Fresh gas in tank or old stuff?  If fresh gas, go to 4.  Old gas can get gunky especially in hot weather.  Drain tank and fill with fresh.  

4. Gas getting to carb?  If yes go to 5.  Close petcock on tank.  Remove line from carb.  Open and close the petcock over a container.  You should get freely flowing gas to the container.  If not, change filter (if you have one).  If not, check for clogged petcock or line.  

5.  In step 4 you also drained the carb bowl, now you should be getting fresh gas in the carb.  Does it start?  If not, go to 6.

6.  Pull spark plug.  Is it blacked up with coating of carbon.  If not, you may want to replace it anyway and go to 7 or just go to 7.  If yes, you have flooded engine.  Crank engine a few times with spark plug out of engine to clear cylinder.  Clean or replace spark plug and try again.

7.  Check air filter.  You may have already done this.   Usually a clogged air filter will not keep an engine from starting, but if it is excessively clogged, it can cause the engine to act like the choke is full on and  flood the engine.

Ok, at this point, you have fresh gas getting to the carb and you are getting spark.  Suspect carb needs cleaned.  See multiple posts by Wolf addressing cleaning carb.  

If you have tried all of the above, post again for next steps.  Good luck.  

sounds like you need to clean out the carburetor and the gas tank shutoff valve.

i would dump all of the old fuel from the tank and start with fresh.

if you remove the carburetor and remove the bowl on the bottom you can clean it out.

use a wire bread tie with the plastic melted off or a .10 guitar string to run through the jets.
although the pilot jet you'll need to either hold the throttle or remove it to get the wire through it.  

Sometimes you can shoot some starter fluid into the carb to get things flowing. Iv'e witnessed for myself what you could call vapor lock where air pockets get caught in carb ports. After you follow the advice of the guys above,(good advice), try this to finish off. If the motor fires up for just a few seconds until the starter fluid runs out, there is definitely trash caught in the carb and you might have to rebuild it .Also while checking the carb float, check the needle and port to make sure there is no trash or deposits inside or that the needle is not stuck.