Help with carbourator that keeps flooding

[TruckintheBoro]

I'm hopeful you all can help...I have a 67 C10 with a 327 that I bought a few months ago. It needed a bit of work and so I took it to a semi-retired mechanic who still has a business working on big propane delivery trucks, but who grew up working on engines before fuel injectors, etc.

Anyway, he cleaned out the carb, installed a new float kit, installed a new choke cable, replaced the starter motor. I got the truck back and ran it for about 10 days, then one day it wouldn't start. Starter was turning, but no engine catch. Then something scary happened...starter motor was turning away and then it came to a sudden halt with a bang from the engine like someone had slammed a heavy door shut.

the mechanic came to my place and said that the carb was full of fuel, that the fuel had been pushed beyond the carb into the cylanders and into the oil. i guess the bang I heard was the sound of the engine stopping turning because the piston was hitting a cylander full of fluid?

they towed the truck back to their place (at their expense) cleaned everything up, changed the oil, and tried to find a cause, but weren't sure what happened. suspected it might be a stuck float at first, but they said that seemed ok. I then drove it for a week fine, but last night it happened again. Very frustrating and potentially very expensive. I am not a mechanic or tinkerer so any fixes or repairs I'll have to pay someone to do. Any ideas on what the problem could be?

[joeydurango]

My carb was also flooding, literally spilling fuel over onto the intake manifold. Definitely had gas in the oil after that happened. Didn't have the "bang!" and lack of turn-over, but similar nonetheless. I assume your mechanic replaced the needle and seat if he rebuilt the carb, but assumptions can get you in trouble - so ask about that. Could be a worn needle/seat, or could be some debris got in there and kept it from seating all the way. How are your fuel filters? Stock, aftermarket, new, old? If they're not clean and new, they could be letting junk through into the carb.

[Redline novdog]

Even if you can't work on it take the air cleaner off after driven . To see if you have fuel spilling over into the intake, you can also do this while the engine is running, but be very carefull. I have also seen mechanical fuel pumps leak from the back side into the engine, filling the crankcase full of fuel.

[snipescastle2]

Just a couple of questions in order to see if we can help out here. Unrelated to the carburetor flooding, but with regards to the "bang" your hearing. Look at your flywheel/ flex plate and inspect your ring gear carefully,make sure there aren't any teeth missing,cracks or other visible damage in the area of the starter drive. You also need to look over the starter mounting boss,where the starter bolts onto the block. Sometimes the block can crack at that mounting position, allowing the starter to "jump" around causing a "bang" since these engines are 90 degrees (rod angles) they have four areas on the flex plate/flywheels that damage will show up on the ring gear.( where the compression stroke starts) You might look at the he did on the starter motor real close, might have a broken tooth there as well.
Now, what kind of fuel filter are you using? Most of the carbs have a sintered bronze (powdered metal) and/or a paper filter,where the fuel line attaches.
if any trash may have been left in the passages that feed the needle and seat (valve that the float opens and closes allow fuel into the float bowl, doesn't take a very big piece of dirt/debris to hold the needle and seat open.... Causing a flood condition. Also, your carb might me " Percolating"-(boiling) the fuel from the engine heat as well.
Just a few things to look for, hope you get it fixed.
Ben

[wesmigletz]

Is this a stock carb? If it is an Edelbrock or a Holley, your stock fuel pump pressure can be too high, causing gas to be pushed past the needle and seat when shut off with the engine hot. Carter makes a stock looking low-pressure pump that will fix the issue. They are less than $25 at Summit.

Wes

[prodjay10]

I rebuilt mine and it was also flooding after. The metering jet was hollowed out and 5 times bigger than the original size. Replaced it and it's been running much better. Not perfect. Sometimes I need to use carb cleaner or gas directly in the carb to get it going again.

[TruckintheBoro]

Thank you!

[TruckintheBoro]

I'm still getting the hang of message boards, but just wanted to say thanks to everyone who provided the thoughtful and helpful responses above.

-Sam