Carburetor Boiling Issue

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Bonkled_2900

Bonkled_2900

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I am having an issue on my 1975 Dodge Dart Sport with the carburetor, it’s a 4 barrel and I went for a drive and when i went to leave from my location, the car wouldn't start and i looked in the carb and there was a constant leak from one of the boosters in the primary side. And pressing the throttle there was only air coming from the nozzles. What’s going on??
 
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Sounds like a Carter or Edel carb. It is flooding on that side:
- check for leaking float [ submerge under warm, soapy water ]
- check for dirt under n/seat.
- check for float binding
- check that n/seats are tight.

The test: invert the airhorn & suck on fuel inlet. If you can suck air, you still have a leak.
 
Bonkled_2900 said:
I am having an issue on my 1975 Dodge Dart Sport with the carburetor, it’s a 4 barrel and I went for a drive and when i went to leave from my location, the car would start and i looked in the carb and there was a constant leak from one of the boosters in the primary side. And pressing the throttle there was only air coming from the nozzles. What’s going on??
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How do you know it was only air? If you could see it, it had fuel in it, since you cannot see air. I would check the float level and the fuel pressure. If fuel is dripping out of the boosters at idle, one of those is likely the issue.
 
Had this problem about a month ago. Needle and seat stuck. Took carb apart and just blew it out. Car still acted funny. Think that I got a load E 15 or worse, I had just filled the car up. It seemed like something wasn't right and then the engine quit. Gas was boiling and dumping out the boosters. I used to haul gas, we called it a miss drop, but never told anyone.
 
I have dealt with the Ethanol here in California for years. Somehow, the only drawbacks that I have seen are early degradation of rubber fuel lines AND the clogging of the carburetor passages if the car sits too long between "runs".
I've measured 140 degrees at the bowls of the Demon 850 in the red car...

493 K.jpg


IMG_9307.JPG


This car still runs fine even in 110 degree heat.
 
Run a return to tank line that should fix the heat soaked fuel under hood.
 
Get a phenolic spacer under the carb if you think it might be a heat problem. A thin one will do.
 
Kendog 170 said:
The plate under carb above will help too. I see you have a Phenolic spacer as well.

View attachment 1716301808
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I have an aluminum spacer. The return is what corrected my boiling issue when restarting it hot. I had the pressure regulator before the carb, I had to buy a return style pressure regulator and install it after the carb eliminating the other one.

I just put a union in place of the existing regulator and ran the new line to the new replacement return regulator. I tried all the heat spacers , They didn't work with this new ethanol fuel .

The reason it floods when restarting is from the bubbling, boiling fuel coming in cannot lift the float against the dead ended pressure to shut the fuel off. The return lets the hot bubbling fuel bypass the carb and allow the floats to work.

Been through this on several builds with all different carburetors. If you have an electric pump you can shut it off and on until you get solid fuel coming in and it will run.

Holley 12-881 Holley Carburetor Bypass Style Fuel Pressure Regulators | Summit Racing

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Bonkled_2900 said:
I am having an issue on my 1975 Dodge Dart Sport with the carburetor, it’s a 4 barrel and I went for a drive and when i went to leave from my location, the car would start and i looked in the carb and there was a constant leak from one of the boosters in the primary side. And pressing the throttle there was only air coming from the nozzles. What’s going on??
Click to expand...
A few things that I have done to help with the hot restarts and E10:

I also added the return line to mine but with an electric fuel pump too. I added a priming button to fill the bowls before each start.
I added a mini starter (Powermaster XS Torque series) to help get the motor turned over quicker on hot restarts.
I also have a phenolic spacer, and I just added a different intake with an air gap between the carb and the block.
 
I've been running 87E10 since year 1999/2000 with zero problems summer or winter. However, our local air-temp rarely exceeds 90* here and alcohol boils at 95 IIRC. In my lifetime, the hottest I have ever seen is 99.
My engine runs at a constant 207. but the 750DP on the AirGap, on the alloy heads, never gets more than warm to the touch. Probably cuz she gets air from above the hood. Hot restarts are a non issue, even with underhood air temps of over 240. Click, vroom-vroom.
But, you know, I ventilated the hood lol,
 
RustyRatRod said:
How do you know it was only air? If you could see it, it had fuel in it, since you cannot see air. I would check the float level and the fuel pressure. If fuel is dripping out of the boosters at idle, one of those is likely the issue.
Click to expand...
There was air and some fuel coming out by barely
 
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