Carburetor rebuild issues

[bwolff0820]

I have a 82 Chevy C10 with the 305. Truck sat for about 15 years. I recently pulled the quad jet and rebuilt. Put it back on today and replaced all vacuum lines. Went to fire the truck and it tried to start but shut off. After cranking on it for a minute I looked at the carb and seemed like fuel was coming out of the top. I also noticed the screw for the throttle that goes in on the drivers side was dripping a good amount of gas. This is the first time ever rebuilding a carb and have little knowledge to these trucks. Is there something I missed in the carb rebuild?

 

[MarineOne]

Sounds like top plate gasket is damaged or top plate is warped. Never seen that screw leak before are you talking the idle screw?

 

[bwolff0820]

So I went back out last night but forgot to get pictures. It seems like too much fuel is getting into the carb. Looked to me like fuel was coming out of the bowl. I found a picture and highlighted the screw where the fuel is leaking out of. I’m not sure if there is a gasket that is damaged or if it backed off during rebuild process.

 

[75gmck25]

One guess - It might be the needle and seat not shutting off fuel, which then floods into the primary and comes out around the throttle shaft (very common to have worn throttle shafts on an old carb).

The first check I would make is that the float and needle are correctly installed, and that they shut off fuel flow when the float bowl is full. Hold your finger on the float picot and then hang it upside down, or with the top still off you squirt water or gas into the float bowl to simulate fuel coming in. Then put a rubber hose on the fuel line fitting and blow into it. Float down- free flow. Float up - no flow at all.

 

[ChuckN]

One guess - It might be the needle and seat not shutting off fuel, which then floods into the primary and comes out around the throttle shaft (very common to have worn throttle shafts on an old carb).

The first check I would make is that the float and needle are correctly installed, and that they shut off fuel flow when the float bowl is full. Hold your finger on the float picot and then hang it upside down, or with the top still off you squirt water or gas into the float bowl to simulate fuel coming in. Then put a rubber hose on the fuel line fitting and blow into it. Float down- free flow. Float up - no flow at all.

That’s a cool trick, I’ll remember that one.

 

[bwolff0820]

One guess - It might be the needle and seat not shutting off fuel, which then floods into the primary and comes out around the throttle shaft (very common to have worn throttle shafts on an old carb).

The first check I would make is that the float and needle are correctly installed, and that they shut off fuel flow when the float bowl is full. Hold your finger on the float picot and then hang it upside down, or with the top still off you squirt water or gas into the float bowl to simulate fuel coming in. Then put a rubber hose on the fuel line fitting and blow into it. Float down- free flow. Float up - no flow at all.

I will give this a try and go from there. Never thought about checking that before I put the carb back on.

 

[fast 99]

The small clip on the needle does not go in the holes on the float, common mistake. Also be sure the float hinge rod is higher than the center housing. Spread it slightly with a snap ring pliers if it isn't. Assume you did not reuse the float and are using new fiber replacement, not brass.

 

[bwolff0820]

The small clip on the needle does not go in the holes on the float, common mistake. Also be sure the float hinge rod is higher than the center housing. Spread it slightly with a snap ring pliers if it isn't. Assume you did not reuse the float and are using new fiber replacement, not brass.

I did make sure the clip was attached to the right spot on the float. I will have to double check that float hinge is siting higher than the housing. As far as the float goes I purchased and new Walker float however it is brass unlike the fiber one that was originally in there. Would that cause issues with the needle not seating right and allowing too much fuel in? This is the first carburetor I’ve ever worked on so it’s all new to me.

 

[fast 99]

Brass wouldn't cause that issue, but most experienced carb rebuilders won't use them.

Fuel at the secondary shaft is likely fuel accumulating on top of the throttle plates. Has nowhere to go but out the shaft. Fix the high fuel level issue that will go away.

 

[bwolff0820]

I will start with making sure the float is adjusted properly and that the needle is seating like it should and go from there. Thanks for the help

 

[Bextreme04]

I will start with making sure the float is adjusted properly and that the needle is seating like it should and go from there. Thanks for the help

There are default starting settings for float height and a bunch of other things. Did you make sure all of those settings were correct?

 

[bwolff0820]

I checked the float height when reassembling. There were some other screws that said to tighten down and back off “x” amount of turns from and did that as well. If the needle is seating properly then I’m not sure what would cause the overfilling on the carb. I will more than likely disassemble and start back from scratch to make sure I didn’t miss anything

 

[bwolff0820]

Does anyone recommend a YouTube or any other tutorial to follow while rebuilding? I found one on YouTube but I’m beginning to think they might have left out some steps in the process.

 

[bwolff0820]

Just thought I would update the post on this one. After doing some more research and tearing the carburetor back apart and rebuilding again got it installed and started it for the first time in 15+ years. Runs pretty smooth now to tack down all the oil leaks

 

[bwolff0820]

Can’t figure out how to post a video on here or I would. Only gives me the option for pictures