- Quadrajet Hard Starting
- Quadrajet Running Lean: What Causes This?
- Troubleshooting Gas Dribbling Out of Venturi in Quadrajet Carburetors – Causes and Solutions.
- Quadrajet Rough Idle
- Quadrajet Carburetor - Engine Surges
- No Vacuum at One of the Ports
- Quadrajet Idles Rough
- Why My Quadrajet Runs Out of Power?
- What Causes a Quadrajet to Bog, or Hesitate?
- What Causes Quadrajet High Speed Lack of Power?
My Thermostat is Located in the Manifold
This is a divorced choke type.
Carburetor is flooding.
Gas is running out of the top, or you get a strong gas smell? This is a sign of flooding. What is flooding? Simply, there is too much gas getting into the float bowl.
Here is a list of items to check when this happens:
- Test the needle & seat. That is the most likely place to have a problem.
- Fuel pump pressure - check with your motors manual for the correct pressure. New pumps are especially suspect.
- Bad float - For brass floats, heat up some water to prior to boiling, then immerse the float. There should be no bubbles. Nitrophyl floats have to be weighed. 6.5-7.5 grams would be great. Get a gram scale here
- Check float level
- Make sure float isn't binding - move it up and down by hand and see if you feel anything catching.
- Make sure float isn't rubbing somewhere.
- Does the seat have a gasket?
- Did all of the old gasket get removed?
- Look for any cracks around the area the seat screws in.
Missing Tubes
Sorry about lack of knowledge and poor terminology. What I was referring to pickup tubes are call the main well air bleed tubes (2 inside tubes ) and secondary accelerating well tubes( the 2 outside tubes) fig. 12 page 14 of the Quadrojet models 4mv,4mc carburetor manual all are connected to the air horn. My carb. doesn't have the secondary accelerating well tubes. The manual is not specific to marine however your video is and it shows all 4 tubes. Looking through your parts section I found pt # 17-91 Rochester carb. brass tube. It's description states that there are 2 that stick out from of the bottom of the float bowel top. I don't have these. My question is should I have the secondary accelerating well tubes and if I do is that the right part # ?
He needs to have all four tubes, 17-91 is one of those numbers.
Quadrajet Carburetor KitsHe needs to have all four tubes, 17-91 is one of those numbers.
Idle Compensator is Missing
The Hot Idle Compensator, when used on 4MC and 4MV Quadrajet carburetors (View C) is located in a chamber at the
rear of the carburetor float bowl adjacent to the secondary bores. Its purpose is to offset the enriching effects caused by
excessive fuel vapors during hot engine operation.
In a perfect world the Idle Compensator should be installed on those applications that need it. Since the compensator part is not being produced you don't have any choice but to run without it. You won't have any problem unless you get into a high heat situation, or use your air conditioner.
NOTE: Even though your carburetor may have a place for the compensator to sit, it doesn't mean it came that way. It was used on vehicles with air conditioning.
What Causes Quadrajet High Speed Lack of Power?
Aneroid
This carburetor is from a '75 Corvette and has the aneroid assembly. I understand that this system is problematic but I would like to repair it. Is there a modification to eliminate the aneroid assembly, and, if not, is there a means by which to clean the assembly?
It’s a lot of trouble to eliminate it, you would have to add a power piston assembly, your better off cleaning and reusing the aneroid. We use parts washer then glass bead and blow off really well. For the adjustment bottom out and come back 2 to 2 ½ Turns.
