This ain't a quick fix, and there's not necessarily any one thing wrong. Most of what you describe sounds like the normal behaviour of old Strombergs.

The only thing you really need to check, is simple. Pull the four screws holding the top cover on each carb, and lift the top. Fear not, it's quite a simple device and it won't drop piles of parts on you; there's only one big spring to keep track of. So. Have a look. Are the diaphragms in good shape? A leaking/split diaphragm will cause absolute havoc. Next, lift the air valve out (lift by the center), and check that the whole carb isn't filled with black ickiness from backfiring or dried fuel, smile if it's fairly clean, then put it back together, and assure yourself all is well. Four screws per carb, and you've checked the diaphragm which is the only real achilles' heel of the Stromberg.

If you check that and don't find a problem, smile and resign yourself to enjoying the benefits of fine British carbs of the 1970s.

Having put over 200k miles on a pair of Strombergs, I can assure you that the hot start problem is normal: Strombergs do that, even when the float is adjusted and the mixture is correct, even when the hot start valve is working, even fresh off a tune-up.

Brand-new Stromberg-equipped Volvos, reviewed by major magazines, exhibited this problem. I can send you the reviews if it will make you feel better. It's completely normal for the type and the more you try to "fix" it the more frustrated you'll get.

When starting a hot Stromberg vehicle on a hot day, put the acccelerator to the floor and hold it until she starts. The flood condition will clear quickly and the engine will start after about four seconds of cranking. If THAT fails, THEN you've got to lean out the mixture.

Rich running is also fairly normal, though I can't stop you from trying to tune it. Basic problem with tuning it leaner: the dashpots that enrich the mixture for acceleration NEVER hold their fluid, so after you've topped the dashpots you'll run well for a few days and then you'll go lean on acceleration. You see where this is going. If you want long-term drivability, and you don't want to fill the dashpots constantly, you just tune it a little rich and live with it. Every Stromberg Volvo I've ever seen was like this.

Idle issues are hard to fix once the butterfly shafts have worn a bit. Air will leak in, and rather than causing a stumble it'll cause a high idle. Because you're running rich, remember?

Fluctuation is pretty normal at high temperatures. It will go away when the weather cools down a bit. There's a certain temperature at which the suckage begins, somewhere around 30-35C. Below 25C, they're pretty good.

Once you get your Strombergs perfectly repaired and tuned, the amount of time they will continue to run asymptomatically will be measured in weeks. Sorry. My car was professionally maintained by a dealer and would do all this stuff within a couple weeks of getting it back, every time.

Don't get me wrong, the Strombergs did make the car go and they never let us down. And they were honestly pretty fantastic in cold weather -- every winter they ran great, started promptly even when we had to dig the car out from under six feet of snow, and so on. Great for cold. They just didn't like heat.

If you want a vehicle with Strombergs in it that idles smoothly, doesn't run rich, and doesn't flood on hot days, simply place the Strombergs into the trunk of a vehicle with those running characteristics.

Nothing wrong with continuing to run a Stromberg-equipped car. Just remember: KEEP IT FLOORED when you start it hot!