Why is the generator running but you cant plug in anything

This site seems to have a decent explanation:

Some portable generators are intended for use on jobsites, and therefore are subject to OSHA regulations for GFCI protection on all receptacles. These "contractor grade" generators have their neutral wire bonded to the ground wire to pass OSHA inspection on job sites. Since home and building main load centers also have the neutral bonded to ground, a loop is created, comprised of the neutral wire and the ground wire. A small amount of current is induced in this loop by the running generator. and since the neutral wire passes through the ground fault sensor, the GFCI senses this induced current and trips the main circuit breaker in the generator.

When using these neutral bonded generators to power a house or building through a transfer switch, the neutral bond wire on the generator must be removed, preferably by a dealer or a qualified electrician. NOTE: After this action, the generator will no longer pass OSHA inspection on job sites. Contact your dealer to determine if the neutral bond can be removed, and we recommend that a dealer perform this task. Honda dealers may refer to Honda Service Bulletin #20 for instructions on removing the neutral bond. Once this is done, no modifications to your transfer switch installation are needed.

If the neutral bond cannot be removed, you have two choices. The easiest solution is to lift the ground wire coming from the generator inside the transfer switch, and secure it with a wire nut, by itself. This eliminates the loop. Your other choice is to install a Switched Neutral Kit (SNK) accessory with your transfer switch, available thru our website.

Note that the generator is still grounded, it's just the neutral bond is gone. This means that the generator does not meet code for stand-alone operation anymore.

So your options are:

• Install a switched neutral kit
• Change to a neutral-switching transfer switch
• Remove the ground-neutral bond from your genset

Here's the instructions on how to do this for Honda generators: http://www.gen-tran.com/assets/pdfs/HondaGeneratorServiceBulletin20.pdf

Here's another good site that explains the issue and how to fix for several other generators: http://members.rennlist.org/warren/gt5000c.html

As gasoline evaporates it leaves a gummy varnish in the carburetor

Gasoline sitting for three years in the float bowl of a carburetor will surely lead to some varnish. The hydrocarbons evaporate from the fuel and oxygen acts as an oxidation catalyst changing the remaining components into other compounds leaving varnish in their wake.

Varnish will coat and clog the inside of the carburetor. Float bowl, floats, needle and seat as well as any jets the were submerged in the gas.

Clean the inside of the carburetor

I would suggest at the very least you remove the carburetor and take the float bowl off. Get some carb cleaner with the little red straw/hose that you can use to spray into jets and and orifices of the carburetor. Let it sit, do it again and use a bowl to capture the runoff. You can let the carb sit in the bowl for a bit if there are trouble spots. Use a toothbrush. Get a thin piece of copper wire you can stick into any jets to ensure they are not clogged. Those are your real trouble areas. Take your time. Be thorough or you will have to do it again.

If you have some extra carb cleaner you can spray it around inside your fuel tank to clean that out a bit too. Spending a little time on the gas tank will pay dividends.

Replace your fuel filter. They are cheap.

If the engine runs with starter fluid, that means you have compression and spark. The last piece is fuel delivery. Focus on that and you will be victorious.

Best of luck.