Stewart carburetor leaking fuel

[22touring]

I tried to start my '22 touring car today, after it had sat for about 6 months. It tried to start, would run briefly and then die. Gas is leaking out of the carburetor. It seems to be coming from somewhere near the bottom of the mixing chamber, not from the float chamber (although I might be wrong).

 

Would anyone have any suggestions? I can't think of anything except a stuck float that would cause this.

[cahartley]

Is it cork float>

Do you drain the bowl in the off seasons so the cork doesn't get gas logged?

Undoubtedly it's the float or needle/seat.

[22touring]

Thanks for the reply, C.A.  I do appreciate it.  But if it were the float, needle or seat, the fuel bowl would be overflowing, right? Instead, the outside of the fuel bowl on my carb is dry, but it is sending lots of raw fuel into the throttle valve area.  The excess fuel then runs down the side of the engine. Maybe a stuck air valve? I really need to remove the carb and inspect, bu have been too busy the last couple of days.

[cahartley]

Oh......THROTTLE area.......

I imagine it's running in a severely flooded condtion........assuming it continues to run?

That indicates a vacuum tank problem.

The vacuum shutoff valve in the tank cover is likely not shutting off which allows gas to get sucked from the tank directly into the engine intake.

In my case it was the other valve which caused it to not pull fuel period but it was intermittent....... 

Purely by accident I saw what was going on when I had the cover off and was working the float manually.

Sometimes the seat would drop out of its place and hang up.

Luckily it was still a close enough fit that a bit of Loctite did the trick.

[22touring]

Wow, you're awesome, C.A.!!  Thank you so much.  I'll check the vacuum tank shutoff valve next.  That would certainly explain the problem.

[Gunsmoke]

Ya, I would carefully all functions of the vacuum tank. A friend of mine had his car restored, flooding of gas through carb, and also into oil pan was caused by malfunctioning vacuum tank. Very dangerous not to mention unhealthy for engine to have fuel in pan. Wound up having a bent lever in top of tank, had to replace with the newer type levers, eventually got it working perfect. Although there are many shapes andv sizes of Stewart tanks, most of the top can be interchanged with little effort. We found a local old parts guy who had 10 spare V tanks, most Steward,all different, but tops almost all interchangeable. Some bottoms of tanks have only one outlet, some have 2. 

[22touring]

Thanks for the post, Gunsmoke.  I guess I'd better change the oil. I had forgotten that the fuel would also go into the crankcase.

I have worked on my vacuum tank several times in the past.  Each time I thought I had it fixed "for sure"!  However, I guess I was wrong.  Or maybe our crummy fuel here in California is gumming it up or something.

[cahartley]

I wouldn't sweat the oil yet.

Smell the oil on the dip stick first.......if there's gas in the oil you'll know...... 

I'm more interested in what you find with the vacuum tank.

[hwellens]

If you are getting gas directly into the intake manifold, I think you will find the float in the vacuum tank has a leak and is not shutting the vacuum off when full. Then the fuel will travel from the vacuum tank directly to the intake manifold.

[22touring]

Do you think I might have caused the problem myself, by priming the vacuum tank before trying to start the engine (i.e., by removing the fuel line fitting from the vacuum tank and pouring about half a cup to a cup of fuel directly into the fuel inlet)?

 

I thought you were supposed to prime the carb that way, but I've been wrong once or twice before, so maybe it has happened again. In fact, maybe what I did was really dumb.  If so, feel free to tell me; I have thick skin.

 

Would priming in this fashion cause fuel to be drawn into the throttle area? (I had thought that the fuel I poured in would just run down into the bottom of the vacuum tank instead, like fuel drawn from the gas tank would do.)  But maybe I don't understand how the vacuum tank works well enough, and the fuel I pour in is going into the throttle area instead?

 

So how exactly would you go about starting your 4-cyl. DB after it has been sitting for awhile?  Does the vacuum tank need to be primed if it is empty?  I'm starting to think my starting procedure may be totally incorrect!

 

I take it that I should be careful to drain all the fuel out of the vacuum tank and carburetor when I put the car away for the winter, right?

 

Thanks very much for your thoughts.

[MikeC5]

I do prime mine if the car has been sitting for more than 2-3 weeks.  However, it's a bit easier since my vacuum tank has a plug in the middle of cap that seems to be just for that purpose.

[22touring]

Thanks for the input, MikeC5.  I am wondering if maybe there might be a big difference between priming into that special plug that you mention and priming into the fuel inlet.  My vacuum tank doesn't have the special plug that yours does.