Quadrajet Replacement Options

[TruDaddy]

Update Time: I got the rebuild kit from Cliff's and put the rebuilt carb on the engine. There is an issue I have never had or seen before.

There is gas coming up the up the accelerator pump shaft and additional fuel coming out near the secondary rods. Obviously something is not correct but where do I start? I am guessing it is the float but I had it set to 1/4. My carb number wasn't on the sheet I was given.

I have heard pushing a small rod through the vent tube could be used to lower the float without disassembly but that seems fishy.

 

[Lou C]

Cliffs has a forum post it up on there & ask

 

[Scott06]

Update Time: I got the rebuild kit from Cliff's and put the rebuilt carb on the engine. There is an issue I have never had or seen before.

There is gas coming up the up the accelerator pump shaft and additional fuel coming out near the secondary rods. Obviously something is not correct but where do I start? I am guessing it is the float but I had it set to 1/4. My carb number wasn't on the sheet I was given.

I have heard pushing a small rod through the vent tube could be used to lower the float without disassembly but that seems fishy.

May not be where the float is set, but the needle and seat is not closing off fuel flow fuel bowl is overflowing

Would take the top off and recheck that especially the gasket on the bottom of the seat whether that is fully sealed off

Could also be too high fuel pressure

 

[TruDaddy]

Regarding the too high fuel pressure...is it common for the fuel pressure to be fine and then it isn't and goes higher? This engine has a mechanical fuel pump. I assume when they go they drop pressure but that is based on nothing.

 

[Lou C]

I'm just guessing here because I have never had that problem but when my float needle wasn't holding one year I had gas leaking out near the throttle plate but not from those 2 areas you mentioned.
Did you replace the accel pump with Cliff's?

 

[TruDaddy]

I'm just guessing here because I have never had that problem but when my float needle wasn't holding one year I had gas leaking out near the throttle plate but not from those 2 areas you mentioned.
Did you replace the accel pump with Cliff's?

Yes, I did replace with Cliff's accelerator pump.

 

[TruDaddy]

Does anyone know what the fuel pressure is supposed to be at? I can test that to eliminate the possibility.

 

[Lou C]

4-6 psi or so.

 

[Scott06]

Regarding the too high fuel pressure...is it common for the fuel pressure to be fine and then it isn't and goes higher? This engine has a mechanical fuel pump. I assume when they go they drop pressure but that is based on nothing.

Would not expect fuel pressure to be in spec (4-7 psi) then be high after a carb rebuild- not my first instinct, only something to rule out.

mist likely something with needle and seat or float. Did you replace the float sometimes the coated foam ones can get damaged when handling … ask my how I know ….

 

[cyclops222]

Call Cliff for what to do.

 

[Lou C]

OK there is one other point, on the Q-Jet float that can cause a problem, there is a little clip on the needle valve, this clip does NOT go in the holes in the float arm, it just clips on the side, if you put it in one of the holes, it can cause float sticking etc. Here's a pic.....see the little clip just aft of the 2 holes.....

 

[TruDaddy]

I was able to solve the problem. It came to cleaning and reassembling the seat and needle and then bench testing per Cliff's instructions.