Carbs need to be rebuilt after setting?

Did the fuel have any stabilizer added to it, before it sat? If not then they may need to be cleaned.

 

The problem would be any fuel left sitting in the float bowls and the carb passages, unless you managed to get that out somehow by siphon/pump/run dry/etc.

 

I'd clean the jets first.

 

Pull the plug wires.

Wind the motor on the starter until you have some oil pressure.

Put the plug wires back on.

Check to see if any carb is pouring gas into the air filter (it is a sign of a stuck float). You will smell the fuel if you sniff about. It will be a BIG smell.

If everything looks dry see if it will start.

If it does (it should) and runs cleanly then check the tires for air pressure and just drive away. If it has a problem that leaves you with one slow -to-warm exhaust pipe THEN start pulling the carbs to bits.

Works for me (although I don’t have a 308).

 

Here's what I would do:
-remove the airbox to allow access to the carbs
-pull all the jets, idle mixture screws, and balance screws, be sure to record the number of turns for each mixture screw so it can be put back the same later
-carefully put small rags below the butterflies, making SURE that you will be able to retrieve them later, maybe tie some fishing line to them for extra insurance
-spray carb cleaner into all the open jet and adj screw openings, and a lot into the float bowl via the overflow opening at the top
-let it sit a few minutes, then pump out all you can via the accel pumps, letting the rags below absorb and catch the liquid
-repeat several times, refreshing the catch rags as necessary
-let any remaining carb cleaner evaporate, probably will take overnight
-put everything back together
-turn the ignition on, let the floats fill, check for stuck float valves, and try to start the car

One note on checking for a stuck float valve, you will probably need to look down into the carb venturis to see an overflowing float on these carbs.

Also, it's difficult to check for a cold exhaust pipe on these cars due to the heat shielding (rear) and general lack of access (front).

I'm sure others here have some ideas too, probably better than mine.

 

Wow, thats a lot of work. I would just add a gallon of fresh gas with a can of Justice Brothers oil treatment mixed in it. After getting oil pressure, start the car and run the whole gallon thru. The entire fuel system will be sparkling clean.
Always use the thin based treatment, the thick stuff is no good.
If the car doesn't run then go for the hard work.

 

Not that hard, probably an hour or two's worth of work at most. Your idea of running some cleaner with the first tank of gas is good, but if you rely on that alone and the fuel feed hole in the bottom of the float bowl is gummed/varished closed, then that fuel and cleaner will never even make it into the rest of the carb.

I would also definitely disconnect the fuel line going into the first carb (front left), and run the pump for a few minutes, catching and discarding the first liter or so of gas.

 

If it were me and I just finished a 2 year maintenance on the 308, then I would spend some time on the carburetion. Especially, if it's been over several years since the carburetion has been gone through. Otherwise any carburetion issues will reduce the performance of the motor.

I would go ahead and purchase the rebuild kits and replace gaskets, diaphragm, and O rings. I would not replace the floats. When you remove the top covers, inspect the bowls for debris. Cheap insurance to ensure their function.

I would also go through the ignition system if not already done.

After every extensive service on my cars, I always go through the carbs and ignition to reset the clock on them.

At a minimum, I would look at the accelerator pump diaphragms. If they are stiff, replace them to ensure good performance. ~ $15-20 each.

Richard