Hmmm there is a couple fuel additives out there that I have heard of. Stabil is a fuel stabilizer use especially for stabilizing ethanol fuel blends and helps keep regular gasoline from going bad too. Supposedly once added to the fuel it can last up to two years. Well the fuel doesn't get to last that long around here so I don't for if it does or not. The other product is Seafoam (brand name) and not the sea foam from the coast so don't run down the coast to get some. It is a fuel system cleaner that can clean borderline dirty fuel systems. Personally I have only used the Stabil additive as I let my generator sit for extended periods without running it.
Normally the carbs here get to go through an ultrasonic cleaning using soap and water. For cleaning out tanks I usually use a 2 cycle mix as usually cleans the best when sloshed around in the tanks. Personally I haven't had a can of carburetor cleaner here in the shop since 2014. The prices of these ultrasonic cleaning machines have come down a lot since the Chinese into making them and liquid household dish soap is fairly inexpensive too.
Now Speedy on the trimmer Walbro carburetor if you get struck on something or have a specific question give me a shout along the model number of the carburetor and I probably can help out. I do quite a few of both the cubes and the rotarys. Some are just not worth the effort however like the Zama C1Q-W32A which has internal accelerator piston that wears both itself and the carburetor area it slides in. One critical area is the setting of the metering lever to the correct height. Both Walbro and Zama have gauge tools for doing this; although, it can done without them. I do Walbro has come a second metering gauge tool for their newer carburetors which are much harder too without it.
Now most Walbro and Zama carburetor do have kits like those Ruixings that have been coming across. The Ruixings are usually a Zama clone so I can get lucky sometimes on the metering diaphragms.
Here also the price of the carburetor repair kits and the replacement carburetor can be fairly close. For a shop it doesn't make a lot of sense to repair as the time to clean and repair carburetor vs just replacing it can cost more in shop time.
