How do i find out how old it is??

Search for part AM106852 but not sure its wise to spend over $100US on a carb for a 15 year old machine. Problem could be crankcase leak.

Should be able to find a different source for under $30. Look for numbers stamped on the carb and internet search those numbers for a different source.

Old bike, old bike problems
You NEED the air filter
Carbs are prob old, worn and need tuning too

First dump out old gas and try fresh. The fuel line to the carb will still have old fuel so a few sprays of starting fluid in the carb will pull the old fuel through the line till the fresh fuel gets to the carb and then it should run.

I would drain old gas, replace with good..old gas can gum up carbs, should drain bowls on carbs also, there should be a screw on bottom of carbs(dont remove screw just loosen till gas pores out)

the most likely problem is; 1-old gas, 2-carb is now gummed up from old gas.

Start off by draining all of the old fuel from the tank, fuel lines and carb. Get a can of spray carb cleaner and clean jets, idle circuit and float valve. you can use a strand of wire from speaker wire to probe the openings in jets.

Pour a large amount of carb cleaner into the gas tank
With choke on full, pull cord often to work carb cleaner into carb and then let it sit for a day or four.
Your carb is dirty for sure.
The venturi and jets are so small on these carbs that they are easily clogged with gunk from old gas

Replaced old gas then i am assuming the bike was not used for some length of time? If you have old gas in the tank and the bike was not used the gas in the carbs would have gummed up the jets in the carb or carbs.
sounds like its time for the carbs to be cleaned.

More often than not, old gas in the carburator breaks down. It turns green and smells like turpentine. This usually fowls the carb inlet. I dodnot know the technical name but You can usually solve the problem by removing the bolt that holds the bottom of the carb. to the carb. It looks like a very small tin can under the carb. This contains the carb float and lets gas into the carb. The bolt is usually hollow and has two extremely small holes that allow gas to be taken up to the carb venturi. They are usually clogged and therefore no fresh gas gets through into the chamber. Use a very thin wire or needle to clear debri. Clean out old gas and residue before reassambley. It could also be the Carb float stuck closed and again no gas is getting through. You can service these issues usually without taking the carb off the motor.

your uncles olds probably has a 425 or a 455 engine in it. anyways, your carb, either 2 barrel or 4 barrel, is 24 years old and is in need of an rebuild. you call call around for an estimate or buy a carb already rebuilt and that should solve your problem. the older carbs will not have the same emissions fittings/hardware and would probably not pass an emissions test.

Get a tee fitting for the size of the vaccum line and connect the advanced line into an existing line from the carb. Worked for me on one of my old cars.