Heres a weird one.. 300 six 1bbl.. I replaced carburetor with a brand new one, made sure everything was connected and torqued down. everything was fine and dandy until the other day i realized when i started the truck and drove it to operating temperatures,and if i would shut it off for 10-15 minutes then go to start it again.. it would just crank and crank?? well... heres the weird part, i took the gas line off the carb and had someone crank to see if i mightve been out of gas or clogged and when my partner cranked it fired right up with gas squirting out of the line????????? sooo when the line was hooked up to the carb it wouldnt start but when i disconnected the fuel supply it fired. I then reinstalled the line and tried to start and it fired right up.. So here i am scratching my head on this to why when i drive it to normal temps why i cant restart it if i shut it off. Also other helpful tips, When i get it to op. temp and shut it off, thick white smoke comes out the top of the carb? as if gas is still being dumped in and the heat is so hot it evaporates. I thought that was my prob was the heat would vapor the gas off before it could be dumped into the intake but im guessing flooding??? and i also hear once i shut the truck off every time there is a dripping sound which at first i thought it was oil falling back into the pan but it sounds like its coming from the carb/intake area? as if gas is trickling/falling into the intake and flooding the chambers causing the truck to not start back up. WHATS GOING ON!?!?!

 

My guess is either vapor lock, or gas is boiling/evaporating out of the carb bowl and needs to be filled up (which turning it over with the starter motor will do).

 

You can look down in the carb with a flashlight and verify if you have gas dripping into the engine.

If you do, then the float level in the carb is too high. This can be caused by the carb float being out of adjustment, or constant dirt going into the carb, holding the needle open.

I don't know if you ever worked on a toilet bowl before, but a carb works the same way. You have pressurized fuel coming into a valve which is controlled by a float that swings on a pivot. All this is located in a chamber, just like a toilet has in the back. The float needs to turn the fuel off when it gets to a certain level. If it's too high, it will spill over into the engine. When the toilet gets too high it spills over into a tube and goes down the drain.

 

How do i adjust the float?