float needle sticking

[irtrimble]

engine will start for a few seconds, die, and then not restart. I have carburetor apart, and needle valve seems to be sticking in closed position and not dropping down with gravity. Could this be problem? Any ideas?

[Al Schober]

Float valve not opening is definitely a problem - no fuel flow.
First is to try cleaning it. Carb cleaner and compressed air is your friend.
If you look at the needle, you'll see that it has a rubber tip. This should be a smooth cone. With age and wear, they do develop a ring depression which could be hanging up. You might need a magnifying glass to get a good look.
Last recourse is to install a new needle, which comes with new seat. Not expensive.

[roadnsky]

Here are some pics to go along with Al's advice.

Also, here is a cut-n-paste of our resident carb expert (Dave Neptune) on setting the float level.
(Hope you don't mind Dave? )

"When adjusting the float, err to the high side of the setting, which is a lower fuel level.

Hold the top half of the carb upside down with no gasket and the float installed, check the height with a scale (good ruler).
The factory setting is 1 5/32" to the bottom of the float, which is on top and resting against the needle which is resting on the seat.

Two things of import here...
1- Be sure the bottom of the float is parallel with the body (this controls the closing position of the float accurately) of the carb, or as close as possible.
2- When tweaking the tabs use a pair of needle nose or duckbill pliers.
DO NOT PUSH, PULL OR BEND the tabs by holding the float itself. Only hold the brass tabs.
Now you can bend the larger portion that attaches to the float for the parallel adjustment and the little tab that rests on the seat for the height.
This can be a bit frustrating so go slow and easy. I suggest that if anything, you set the float a bit HIGH @ 1 3/16~1 5/32.
These adjustments are important to control the emulsion wells that mix air into the fuel to break it up! The factory adjustment specs are 1 5/32 +/_ 1/32" which is why you need it to be as parallel as possible. I run mine at 1 7/32 and like the way it performs."

[Al Schober]

Great photos, road!
My carbs have a little spring thing that keeps the needle from escaping.

[irtrimble]

Thanks. Rubber tip of needle looked OK. I tried to clean the seat; a golf tee seemed about the right size. At any rate, when I reinstalled the carburetor, engine ran smoothly with apparent good fuel supply. If it happens again, I'll try the whack it with a hammer trick first.

[capnward]

Cleaning the seat is the usual fix. The question remains, why did the needle stick? I think if you use MMO in your gas, this is less likely to happen. I also think ethanol softens the rubber, but I have no scientific evidence for that.