how to use carburator cleaner and engine conditioner for cars and bikes

my 10 yr. old son doing a scooter's carburetor overhaul

Using the carb cleaner has pros and cons. The good thing about carb cleaner spray is that it will clean the unwanted deposits (carbon build up and sludges). Doing a full carburator overhaul is the best thing to do but if you want to clean the valves a bit, engine conditioner and carb cleaner is for you. Remember that these chemicals will damage palstic and rubber parts so be very carefull when you use them. If you are working on a carburator or EFI, it is best to put a rag under the carb/EFI and be carefull not to drip these chemicals especially on electronic parts. Dont get too paranoid because they wont give damage to plastic and rubber parts that easily. 


1st get your engine to warm up. Remove the airduct from the air filter. Get a rag and spray the chemical on the rag. Open the flap and stick your finger in and clean the area especially on the edges of the flap. 
If you want to go further to clean the valves a bit, spray the carburetor / EFI with cleaner/engine conditioner inside the throtle body but make sure that you try to minimize (best if none will enter) the hole just in front of the flap on EFIs because some holes are mostly for electrical units. Do this while the engine is running to get best results but for EFIs with air flow meters, it is best to do it while the engine is not running because if you take the air duct the engine will stall. You can still do it but you have to stick in a long hose in the air duct just after the air flow meter and redo the clamps. Spray around the throtle body and control the engine's throtle by pulling the cam or cable. DO NOT OVER DO THIS AND DO NOT OVER REV. If you do this for a long time there may be oil shortage on the valves and you'll fck the engine. There will be lots of white smoke from the exhaust and try not to inhale the smoke. I quarantee that a normal person without asthma will have asthma if he sucks too much of this white smoke. While doing this, the engine will run funny or will stall but after the routine, your engine should run OK and if not do a full carb overhaul. 

It is not advisable to do this on 2 strokers especially for racer models because most racers oil mixture is low and 2 stroke engine's design is different from 4 strokers. In 4 stroke engine the crank have oil inside the crank case unlike 2 stokers which oil is only pumped inside or oil is premixed with fuel. If you over do this on a 2 stroker, the crank bearing's grease may be washed away causing the bearings premature break down. I do it sometimes on my race bike but I change the crank bearings every year and this may not be a good idea if you don't know what you are doing.

After doing this, spray a bit of CRC/WD-40 on the pivot point on the flap and put the parts back together. Now remove the spark plugs and clean it with a wire brush because there will be soot build-up in the plugs. Start the engine and give it some quick revs until the white smoke is not visible anymore. 

NOTE: There are time that people will think that the carb needs an overhaul but the true problem is damaged vaccume hoses. Carburetor hoses sometimes crack-up from age, vibration and heat from the engine causing unsatisfactory engine performance. The cure is to find the cracked hose, cut the damaged part and re-install it. Hoses are cheap so best to buy a new one to save you from future headaches. Older Nissan Sunny, old Toyota Starlet, etc. is famous for this problem. 

Again be very carefull using carb cleaners and engine conditioners. If you spill some amount below the unit, wash it out with water but be careful not to let water enter the spark plug holes or the distributor. And since these chemicals are flammable, best not to smoke your cigarettes and just enjoy the sweet white smoke coming out the exhaust :) ... cough-cough-cough... hahaha!