hi ,i have a 1941 Windsor convertible with vacamatic ,seems to me like the dash pot on your carb may not be helping ,rebuild the carb including the leather dash pot and adjust the idle ,should cure most problems .In my experience of fluid drive ownership its most unusual for them to need flushing and new fluid ,simply topping up has always worked for me. my key for the ignition unlocks both doors. Ive had the car 6 years now and after rewiring and fettling it runs like a champ, mind you the triple carbs ,twin exhausts and headers do help!