I have an Old FB100cc Suzuki Motorbike the prob is everytime I turn on the petrol it floods the carby, turns up the revs,leaves a trail when I slow down or stop and comes out the over flow

Sounds like yr idle is to slow. most cars idle around 650 - 750 revs, increase idle. Usually a screw or nut turn does the job. Or yr a spark plug could be shot, if old replace them all, or petrol pump playing up, check wiring connection at tank- with power turned off, no sparking in case of petrol leak.

No easy way really, the best way is to get hold of an external electric petrol pump, put this inline before the diesel lift pump (With plunger on top in engine bay) and run a hose from this into a container, you then supply power to the pump and wait for it to drain, Make sure you tow the truck to a gas station and fill it completely with diesel to dilute any remaining residue of petrol to avoid engine damage and make sure you don't rev the vehicle as soon as you start it, leave it to idle for ten mins or so to avoid injector damage.

You have a sticking float in the carburator, due to old gas, or dirt. The float moves a needle that turns on and off the flow of fuel into the carb bowl.

Hi, from your question it sounds like you have an idling problem. To fix this you have to adjust the idle speed screw that is located on top of the carb. Turn that screw in (clockwise) for faster idle speed. Hope this helps. All the best and good luck.

sounds like flooding, carby service maybe required I'm guessing that it has been sitting for some time ,fuel has a tendency to go like jelly then hard like super glue and it blocks all jets
all machines that are small and that don't get used often should have a fuel turn off tap so you can run it dry (carby empty of fuel) meaning, whilst running, turn tap off, engine dies,carby empty no problems!!! it seems to be a common prob with small engines and all service centers are praying on this happening ,hope it helps if you are able put a fuel tap on approx cost $4 or get someone to do it ?

Check you float needle is not stuck ,and is not shutting of the fuel

before you stored it for the 3 months did you drain the carbs and petrol tank... if you havent then your probably right to think that fuel isnt flowing to the engine.. overtime petrol additives eveporate leaving a gunky residue in the float bowls of the carbs and clogging up the jets... so drain all the old fuel, clean the carbs and hopefully that should get you back on the road

Sounds like needle & seat in carbys could be sticking or float levels maybe to high when you turn your key on your fuel pump starts and this puts pressure on needle & seat and if floats are to high the petrol just keeps flowing Float is what stops petrol flooding the carbies, check minor things first like dirt in needle seat if you have a compressor give carbies a light blow out.

if its an old caburator style, it sounds like it has a bad float , --i have seen cases where the float would be slightly pourus and gas would seep inside making the fload heavy and letting it continuously flood out....hope that was helpful!!

An obstruction like a piece of foam from the Air filter may be where it shouldn't.. Check for shorts cause on my GSXR 600 SRAD the wire couplings tend to melt back under seat on left side tend to short an melt plastic. Near voltage regulator..