74 B120 stock hitachi carb drains the float valve overnight.

[spottedog]

Stock fuel pump too.

[datzenmike]

Can't flow up hill and back to the tank. Has to be leaking into intake if you don't see or smell gas.

 

The jets are in holes covered with plugs just under the front sight glass. Any wetness there after shut off?

[bob3d]

My dch drained after 3 days. Bought a reman carb does the same thing.

[datzenmike]

Then front cover sight glass cover or jet plugs on front leaking. The plugs use copper washers.

 

 

Has less than a 1/2 cup of gas. When engine warm it probably evaporates fast and not noticed.

[bob3d]

No external leaks. Put a paper towel under the sight glass and main jet plugs and watched for 3 days. No stain or gas smell on paper towel. Happens on both carburetors. Have not spent any time on the problem yet so i will try to figure it out. Yes maybe evaporation from heat. I did not use the extra thick paper gasket. DCH306.

[datzenmike]

 

Well you could remove the carb while full of gas and do the same thing. Watch the underside for dripping. The only way out is down. There is a hollow screw that comes up from underneath and holds the throttle plates to the main body. It allows a manifold vacuum signal up inside to make the power valve work. (I know this because someone had my 710 carb apart and put it together with the hollow screw in the wrong place. What a difference with the power valve working) Maybe gas getting out through this or a crack?