Terry Blow speaks of the importance of a fuel filter for the Heashung

I imagine it would. Having no experience with gopeds other than a couple rides on a neighbor's as a kid, I say:

If not, you can always get one aftermarket from an auto parts supplier.

Leaf blowers, weed whackers, chainsaws, etc. all have small ones built into the gas tank. Basically the same throughout small 2-strokes. It's just a small tube akin to a fish tank filter. Hope this helps.

If the goped is new from the factory, it should come with a filter on it. If it is used, no guarantees. If you need one, go to an auto parts store such as advance or auto zone, and ask where the small engine section is. There you will find several to choose from. Make sure you get one that has a nipple on both ends. Installation is very simple. Make sure the fuel valve on the tank is shut off, take a pair of scissors or diagonals and cut the fuel line and hook each end of the fuel line where you cut it to one of the nipples on the filter. If the filter has an arrow on the side, be sure to install the filter so the arrow is pointing the opposite direction of the tank, not towards it. If the filter does not have an arrow on the side, it does not matter which direction you install it in. Once the filter is installed, you may want to check the flow. You can disconnect the fuel line from the carburetor and turn the fuel on for a very brief second, just to ensure that gas is coming out. Once you see that it is (it will not take very long at all), immediately shut the fuel off again and re-attach the fuel line to the carburetor.

Every goped I have seen uses a diaphragm carburetor like a Walbro.
Walbro image at Staton
They use a filter that fits onto the end of the feed fuel line inside the fuel tank.
Filter image at Staton

The HuaSheng 142f does not use this type of carburetor.
It uses one of these: Carburetor image at Bicycle-Engines
They are best filtered by this style of filter: Filter image at Amazon
They have an arrow that indicates the direction of fuel flow through them to aid you in installing them facing the correct direction.

Here is a good picture of one installed on one of scotto-'s bikes:
http://motorbicycling.com/showpost.php?p=478684&postcount=8

Woah! Hit the brakes!!!
After watching the video link you shared in your other thread your scooter does in fact have the Walbro style diaphragm carburetor and fuel filter setup that I first linked to.
There is no reason to add another in line filter like the one I linked to at amazon or scotto- has in the photo I linked.

You have a HuaSheng 142FL engine, not a 142F engine.
I am sorry I misled you. I had the wrong engine in mind.

Here is a link that shares a bit more info on it from Grubee.
http://www.grubeeinc.com/USA/4 cycle kit rear mt.htm