Sticky needle valve

[hull 433]

I've had a sticking needle valve in a Holley G. I've cleaned it with acetone and reinstalled it in the carb, but still wonder - what causes the stick and how can I prevent it from happening in the future?

[TXGOAT2]

Is it the needle or the joint in the linkage?

[speedytinc]

Possible varnish build up on the seat. Take a sharpened dowel & twist on the seat. That black transferred mark is varnish.
To the eye, the seat may look clean, but the dowel tells the tale.

[Humblej]

Mixture needle or float valve? Mixture needle is strictly the mechanical tension on the collett or tension of the u-joint tabs, the float valve will stick due to gasoline and additive residue. One needs a mechanical adjustment once in a lifetime, the other cleaning every year or so.

[hull 433]

It's the float valve. I got some residue out yesterday, will try again today. Thanks for the input.

The engine and carb were rebuilt thirty years ago, but the car has not been fully reassembled until recently. I've started it a few times while troubleshooting an oil leak, but have not had it running for any length of time, nor on the road.

The carb was clean, no problem at first, sticking only recently. The fuel is name brand gas station fuel. There was a bit of residue in the tank, but the sediment bulb has caught most of that. Maybe some got past.

[Norman Kling]

Some of the new fuels will turn to varnish if they stand too long. So if it was started and then not drained if parked a long time (over a few months) the fuel will jell and either clog the fuel line or the needle valve or even the passages in the carburetor. So if it is to be parked the entire system should be drained or at least turn off the fuel at the sediment bowl and drain the sediment bowl and run the engine until the carburetor runs out of gas then drain the remainder out of the carburetor. If you have an auxiliary shut off near the carburetor, close it too just in case the valve on the sediment bulb should leak a little into the line. Anyway, at this time you should probably run a wire in the fuel line then blow out with compressed air. Also might need to completely clean the carburetor and blow out all passages.
Norm

[hull 433]

Thats interesting, Norm. A friend of mine who was just up in Prineville for the HCCA tour lets his cars sit between tours and seems to never have a problem. Another friend, up in Plymouth, drains his tanks religiously. Oh the gas gods.

The gas in my car was definitely sitting a few months. Fortunately I recently drained the tank while hunting down a slow leak at the sediment bulb and have a second shutoff on the carb. I'll give the fuel line a run, reinstall the carb and keep it cleared out between runs. The gas definitely has a residue.

[TXGOAT2]

Dirt, rust, or fuel residue will cause the valve to stick. Mechanical wear can also cause it, and in some cases , the float leaks or is deteriorated or is rubbing the side of the bowl. If there is dirt or rust in your carburetor, you can expect to find dirt or rust in the entire fuel system.

[CudaMan]

Some '60s and '70s Carter carburetors had a little clip that attached the needle to the float arm, such that when the float dropped, it physically pulled the needle off of its seat. If you continue to have needle sticking issues, you could look into obtaining one of the Carter setups and adapt it to your carb.

[hull 433]

Thats an interesting idea, Mark. The only change to stock so far is a new float.

There was a bit of crud in the tank Pat, but that seems to be gone now with the first fill and drain. I'll hunt around for any more.

Right now the needle is moving smoothly with no sticking. The acetone did its job. I'll give her a tad more cleaning and install today. It will be nice to hear that engine running.

[CudaMan]

Here's a link to one source for the needle with clip so that you can see what it looks like. Some Quadrajet carbs used a similar arrangement.

https://allcarbs.com/product/edelbrock- ... -assembly/

[bron-hertford-nc]

For needle and float valves what I found works is non -ethyl gas with Sea Foam auto/marine/fleet treatment - in our area available at Ace Hardware and most auto parts stores - white bottle with a red emblem. My test cases are my 3 MGs (47.48.51) with SU carbs - which are notorious for needles and float valves gumming up after just after a month and not starting when using regular gas - non-ethyl helped, but Sea Foam worked wonders (an ounce to a gallon of gas)
Started them up yesterday after 4 months sitting and all started with just a few turns. On the T's with choke out and 3-4 turns of the starter and stop, get a lot of starts with just turning the key to Batt.

[TXGOAT2]

Where do you get ethyl gas?

[bron-hertford-nc]

Sorry - That's Non -Ethanol that you want - we find at a number of gas stations and boat marinas. Then add the Sea Foam.

[KBurket]

Here’s a link to find gas stations that sell non-ethanol gas.
https://www.pure-gas.org/

[Dan Hatch]

FYI: For cleaning the seat use a bamboo chopstick. Sharpen the end with pencil sharpener, spin the chopstick with your hands like you are trying to start a fire. This with clean and polish the seat. Dan