man.. that can be a real pain for sure.. I've been there, and never really fixed it. Rather, the problem would finally go away after fixing a whole lot of stuff....

Likely, the fuel is boiling in the floats. That seems to have been my problem usually. If the car is doing it's offending behaviour, get out (filters off), lift the piston in the carb. Can you see fuel spitting from inside as though it's boiling (car *not* running)?

First and foremost, get them phenolic spacers in there. Make sure you have the correct heat shield(s) (for HS6 with outside floats, it should have the single shield in the middle)

All that said, I've tried doubling up phenolic spacers, using various combinations of dual heat sheilds (and two spacers/carb)... higher octane gas, gas additives... aluminum foil on the jet tubes and/or fuel lines... you name it.

I'm assuming your gas is fresh... but how much ethanol are they forcing upon you in your area?

I'd say, first order of business is to get them spacers in there. Second would be to switch to the dual aluminum intake/iron exhaust manifold setup. Then experiment....

and what the heck. Go for additives... maybe even diesel, though I don't know if I'd go for a full gallon yet. start small... your tank ain't that big.

The one thing that really did help in my case was to unlatch my hood.. but my issues were in a 1800 where the hood opens next to the windshield. But if you can get some added airflow.. it would probably help.

good luck! I feel for you. Some seem to do this, some don't... I think it's really a problem with modern fuel quality that boils at a lower temperature than the Volvo SU low fuel pressure setup was designed to use what with the exhaust manifold right there under the floats...




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-Matt I ♥ my ♂