2001 dt200 carb'd won't idle

[salty80]

This motor ran fine last year, after storing for the winter it will no longer idle. Replaced the topside fuel tank, rebuilt carbs, replaced fuel pumps. Engine starts fine on choke, and will stay running by either keeping the key pressed in for choke or by intermittently pressing the key in (before it dies). Seems like a fuel issue, but I'm starting to wonder if it could be electrical, a sensor, or something else? Hoping someone reads this who has experienced this before or is at least more of an outboard mechanic than I am! Would also like to know a good link to the service manual.
Thanks in advance...