My 1969 145 is getting old240,000. Lately I've had this problem where after driving for 20 minutes or so, I'll shut it off to run an errand, come back, start it up, put it in drive (automatic) and it stalls. It will continue with this pattern until I start it again andgive it a highrev in neutral for about 20 seconds, then it will run without the stall.
I have dual Strombergs and am wondering if one of the carbs is bad, or the evaporation device is dead...any ideas?

Also, when I let it idle in neutral the RPM's climb so high that I have to shut if off and quickly re-start it to grab the low RPM, before dropping it into drive.

Thanks