Cuda 340 Thermoquad unstable.

[jimynick]

There are two nice and black O-rings in the black float bowl that're easy to miss under the booster bodies, that lay in the float bowl and the carb will run like ka-ka without them. Just something to check. 

[Manuel]

Yes, hard to believe something so basic was not detected right from the beginning.
Maybe its something new from so much touching.    Actually I was the one who discovered it, the mechanic said he had not felt any fuel inside the  floats before.
We will see what happens with the new ones.

I had the intention to send it to the USA but the mechanic wanted to try a new repair kit and give it a last shot.

[Manuel]

I will keep that in mind.    Thanks.

[Manuel]

Car was tested during the week end.   Problem went away with the floats change.

Hope its end of case.   Thanks for the inputs.

[Manuel]

Update,

If the car is not used say 5 or more days y have to pump the gas pedal some 5 times and it will start.    No problem with that but so you know.

Once started all is fine.

Unfortunately maybe 20% of the time once I stop the engine and try restarting it after say 20 min it will not start.
I have to push the gas pedal all the way in, hold it there and then it will start, floded I guess.     

Gas here in Guatemala has no ethanol.

What might be the reason?

[DeathProofCuda]

What might be the reason?

Pretty normal operation for a carbureted car.  Carbs are vented to the atmosphere, not sealed under pressure like a fuel injection system.  Over several days, gas in the fuel bowls will evaporate so the fuel bowl(s) need to be refilled before the car will start again.

When a carbed car is already warm, it is normal to have to hold the throttle part way down to get the right mixture for starting.  If the carb is hot enough that fuel is boiling over into the venturis, flooding it, then you may have to hold the pedal all the way to the floor to get it to start. 

The next time you shut it down hot, look down into the venturis to see if fuel is boiling out.  If so, you may want to try insulating the underside of the carb with a spacer.  If not, I'd say your car is operating normally.

[Manuel]

Thx for the comments.

What material do you recommend to insulate the underside of the carb to engine area?
Its like putting an extra gasket/seal right?    Not a mechanic...

I have owned the car 48 years and did not drive it for maybe 6 or so. Just turned it with the starter once in a while.
During the previous say 42 years I do not recall it giving problems when hot.
Maybe I was just lucky and now its just as most of them...

I will look inside the carb for the venturis as you point out.   Good idea.