Engine stumbles on startup

[ArtJ]

I have a late model A4 in my 1970 Tartan 34

It has been running great all season. I installed a new carb in the
spring. I have electric fuel pump. Igniter elect ignition as well as
protective dropping resistor with coil.

Yesterday, the engine started perfectly a ran for a couple of minutes
then started to stumble and died. I attempted to restart to no
avail. I tehn noticed the smell of gas and checked the throat of the
carb and it had gas dripping out of it. I also noticed gas and gas stains
in the bilge. I cleaned all of it up. Looked at the choke to see if
operating properly believe it is but could not easily look in the
barrel.
I may have 2 separate issues, can excessive gas cause flooding and a shutdown? I noticed elsewhere that someone had to replace fuel shutoff
due to a starting problem. I thought that the draft of the carb
precluded flooding? or could the choke being on cause a excess of
fuel to drip out stuck float? leaking main fuel shutoff?
the tank height causes gravity flow of fuel on the Tartan 34

Do I have 2 problems?

Comments Appreciated

Art

[Dave Neptune]

Art, there are a few ways for fuel to leak out of the throat.

First and most common would be a stuck float. Do you have filters on the fuel line?

Second and not as common is a compromised float. That is a float with a leak that can hang down leaving the needle open. This will usually cause a flood of fuel not just a leak.

Third and not so common would be lugging the engine or leaving the choke on. An updraft carb running rich, with the choke on or lugging can cause a poor fuel mix and that poorly mixed fuel will stick to the walls on the way up only to leak back down as it is liquid and not vaporized fuel.

Only in a serious over-rich situation will the excess fuel stall the engine.

Do be sure you have a good spark too.

ANY CARB MOUNTED WITH A POSSIBLE GRAVITY FEED SHOULD HAVE A FUEL SHUTOFF VALVE FOR SAFETY!!!!!!!!!!!!!!! A good place to mount the valve is on the fuel pressure gage in front of the carb.

Yes an updraft carb can flood an engine!!

Dave Neptune

[Dave Neptune]

Part II, does your scavenge tube still function? IE is the tube "clear and free of obstruction" and are the fittings tight?

Dave Neptune

[ArtJ]

Thanks Dave apreciated


I have ordered a new shutoff valve today. the original is probably 50 years

I will install it to carb.
I will recheck scavenge tube connections

I was wondering about the choke being on. I will check more carefully
tomorrow. The only thing that threw me off was the quantity of fuel and the stains in the bilge Can the choke being on cause lots of fuel to be coming
out of the carb?

. It has run perfectly till yesterday
The carb is new and new filters in the spring,

Thanks Appreciated
Art

[Dave Neptune]

Art, if the choke is on it will draw an excess of fuel that is not very atomized into the throat and a lot of it will stick to the sides only to "run down" the throat and out. It is the scavenge tube that reroutes (sucks) that fuel back into the intake manifold. If there is to much fuel the engine will flood!

Do a visual check of the choke by removing the flame arrestor.

Dave Neptune

[ArtJ]

Thanks Dave

The choke is normally spring loaded to be open I believe, but I will
check to be sure.

Much appreciated

Art