why are my plugs wet with gas and the engine floods out after a minute?

J

jayocular

Member
i have a 56 buick and my motor keeps flooding .it is the rochester 4gc carburetor.the floats have been triple checked on measurement and are fine.plus,this carb has a screw at both primary and secondary chambers so if your floats are too low or sinking,the gas will come out when you remove the screws and it isnt so i know its probably not the floats.the jets are the proper size.the fuel pressure is right at 4 pounds when running which is normal.the carb has been completely rebuilt and new everything.ive checked that the needle valves are clean and do not over tighten them.
b4 it floods the plugs,it starts right up and will run until the engine barely starts to warm up and it will stall.then of course i cant start it due to wet plugs.ive tried leaning it out when it is runnning but it makes no difference in how the engine is running.i cant time it without it being warmed up either but it is within range since i static timed it.what gives?
could it be an intake leak?also there are these small holes on the carb base stand,1 above each bolt mounting hole that dont seem to make sense.i see drizzles of gas come out of each too when its done running.should those be plugged?are those causing intake leak?they look like they are supposed to be there but dont know if they should be sealed or not.seems to me that there should be no holes beneath the carb like that.
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Have you tried plugging the holes under the carb? Are you sure you timed it right? If you haven't the engine may only run under certain conditions(cold)? Have you tried the WD-40 trick to locate vacuum leaks? Lastly have you put a vacuum gauge on the engine. This tool can be very helpful when diagnosing internal problems.
 
flooding

is that a brass or copper float or man made material ?the man made material soaks up the fuel and sinks. Causing flooding. Put the float in some gas and leave it over nite se if it is floating or not. also needle and seat may be bad. If you have ever adjusted the float and just pushed it against the float that will damage the needle. I hope helps.:hurray:
 
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"starts right up and will run until the engine barely starts to warm up and it will stall"

does the choke open?

Have you opened the carb to see if everything is as it should be? my 64 was flooding;
opened it to find a keeper clip had fallen off and was keeping the needle from closing.

the holes in the carb have me confused... are these all equal sized? does the vacuum
advance connect to the carb or to the manifold? on the 300, the straight nipple to the
vacuum stayed in the hose when I pulled it apart. it goes in a "hole" in the carb lower
body.

I second the suggestion of a vacuum guage - I tune my engines by them. on the Wildcat
(64, 445) I have one permanently mounted in the engine compartment and one in the dash.
:shield:
 
WildKitty said:
"starts right up and will run until the engine barely starts to warm up and it will stall"

does the choke open?

Have you opened the carb to see if everything is as it should be? my 64 was flooding;
opened it to find a keeper clip had fallen off and was keeping the needle from closing.

the holes in the carb have me confused... are these all equal sized? does the vacuum
advance connect to the carb or to the manifold? on the 300, the straight nipple to the
vacuum stayed in the hose when I pulled it apart. it goes in a "hole" in the carb lower
body.

I second the suggestion of a vacuum guage - I tune my engines by them. on the Wildcat
(64, 445) I have one permanently mounted in the engine compartment and one in the dash.
:shield:
Click to expand...
well by holes i mean little pin holes and there is one in each corner right above the mounting bolt holes are.they are equal size which is what is puzzling...they look like they are mean to be there but make no sence.they are on the carb stand so it seems there should be no leak there and when the motor is really getting high on idle,i see little drizzles of gas coming out of some of them sometimes.
1 thing i dont think i mentioned too is that i only had the thing running a few times and a total of maybe 10 minutes,and it sucked down about 2 and a half to 3 gallons in that short time and its done like that another few times when i first got it started.seems to be way too much gas to me.
as far as a vacuum,i havent done that and have never b4 so i dont know how or what i need to do that.could u explain if u would?
and as far as the vacuum advance,it connects nearest to the intake on the carb stand right at the bottom of carb stand.
by the way ,i appreciate your response and would really appreciate further help!
 
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2.5 - 3 gallons is way to much fuel in 10 minutes! That car shouldn't burn that much fuel going down the highway pretty fast. I think we should back track some. About the only way the car could suck that much gas is with a severe carb problem or way to much fuel pressure. I would almost bet that your needle and seat are hanging wide open, either due to a problem with the needle/seat assembly itself or a float problem. Excessive fuel pressure can force feed the carb and push open the needle/seat, but that's less likely unless you have an adjustable pump or a return line is plugged.
What happens if you restrict or stop fuel coming into the carb with a clamp or something? If the needle/seat or fuel pressure is the problem and you restrict the flow into the carb the engine should smooth out and run a lot better until it runs out of fuel.
I also agree that the choke could cause the stalling issue, try wiring it wide open.
 
the rebuild kit should have come with an exploded view of the carb. heaven forbid someone threw that away.. was the kit mail ordered or purchased locally. if locally, ask the parts store to look at the instructions/diagram. if by mail order/online, google the supplier, get their # and call their customer service - they would probably send you the needed diagram.

I second the suggestion of cutting off the supply and see if she runs smoother on the gas that's in the bowl. be sure to disconnect the supply line to the fuel pump or you will have a stream of gas shooting out. when I fired up the 327 after it had set for 10 years, I hooked up a "IV", hanging from the hood, that gravity fed the carb - I didn't want to pump anything thru the carb from a tank that had set for 10 yrs.

three gallons in ten minutes puts a whole new spin on MPG.. that would be 18gals per hour.

a vacuum guage comes with plenty of instructions on how/where to install it + how to read it... worth every penny.
:car:
 
WildKitty said:
the rebuild kit should have come with an exploded view of the carb. heaven forbid someone threw that away.. was the kit mail ordered or purchased locally. if locally, ask the parts store to look at the instructions/diagram. if by mail order/online, google the supplier, get their # and call their customer service - they would probably send you the needed diagram.

I second the suggestion of cutting off the supply and see if she runs smoother on the gas that's in the bowl. be sure to disconnect the supply line to the fuel pump or you will have a stream of gas shooting out. when I fired up the 327 after it had set for 10 years, I hooked up a "IV", hanging from the hood, that gravity fed the carb - I didn't want to pump anything thru the carb from a tank that had set for 10 yrs.

three gallons in ten minutes puts a whole new spin on MPG.. that would be 18gals per hour.

a vacuum guage comes with plenty of instructions on how/where to install it + how to read it... worth every penny.
:car:
Click to expand...
i havent yet pinched off the line but did check fuel pressure when it was running and it only got around 4 pounds which is normal.
the vacuum system i think im going to look into,never hurts to have one.
as far as the carb,i did order it online and do have the diagram and everyone keeps pointing at a fault in the carb so i think i might just suck it up and take it apart again and go through making sure everything is proper and nothing is missing.i know when the car is idling i dont see any fuel coming out of the primary jets,so that is good.when i give it gas,i see a healthy stream coming out of them so the problem must be in the main jets or somewhere on the bottom of carb.im not really experienced much in carbs and my friend is the one who rebuilt most of the carb and kind of explained the processes as he went.it wouldnt hurt for me to learn by rechecking it.it comes with complete easy to read instructions so it shouldnt be too bad.my friend is a stickler when it comes to doing his work the right way though and double and triple checks his work and was excited when i let him build it.we also cleaned the body of it and ports all thoroughly so it just seems wierd that the carb is the problem.
i appreciate your help here by the way
 
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