Seafoam and such cleaners can sometimes make the problem worse as I guess you found...they clean all the crap out of the tank, which then plugs up the fuel filter. Give that start your engines a go now there's a fresh filter.
"Cold blooded" is redneck for too lean. Engines need a rich condition when cold to counteract the fuel that condenses back to liquid droplets on the cylinder walls and doesn't burn. Remember liquid gas does not burn, it's vapors do. So even though the carbs are metering in the correct amount of fuel, the actual burn is lean. You need "too rich" metering to achieve an "ideal" burn when cold. As the motor warms up and the cylinder walls heat up, the gas no longer condenses from contacting a cold surface, and you no longer need the choke...and why a hot motor will run like poo with the choke on.
"Cold blooded", as in something takes a long time to warm up, is because the incoming mixture is knife-edge lean to start with(even for a hot motor), so the burn will be too-lean until the motor is fully warmed up and very little/no gas condenses. Correctly fueled motors will start to run OK after typically a few seconds, since there's a little extra fuel to go around if a bit continues to condense, it'll still run OK(with a smelly exhaust). The Vmax is a big motor, with a lot of oil, and a lot of coolant. Mine will take 10-15 minutes of idling to reach normal operating temp (180* coolant temp), and up to 30-45min of driving for the oil to reach it's peak operating temp.
Turn your a/f screws out in 1/2 turn increments. To check if they're in sync, pick one of the screws, and turn it in until it bottoms, noting how many revolutions(a piece of electrical tape on the screwdriver to act as a flag helps with this). Then back it out the same number, and repeat with the others, setting them all the same.
