The rope of the TB90BC Spring Assist string trimmer will not recoil back. I do not know how to take the housing assembly off to even determine what parts (if any) I need to get the rope to recoil back in so that I can start it.

Can anyone tell me how?

Hi,
You can get a manual (if you do not have it) from OwnerIQ: Product user manuals, help, forums tips and tutorials. (http://owneriq.net/) which of course does not cover it.
You can use the next link to see the parts breakdown (Parts Lookup, Troy-bilt, Handheld Products and your model info) http://www.milacalawn.com/parts.asp
You will see that shaft/clutch housing comes off, then the clutch drum and clutch, and finally the starter housing to access this area.
Peace,
Clarke

Troy built tb90bc trimmer starts but stalls in 5-10 secs,replaced fuil lines and bulb,but still has air in lines and stalles in 5-10 sec.

troy built tb90bc trimmer starts but stalls in 5-10 secs,replaced fuil lines and bulb,but still has air in lines and stalles in 5-10 sec.

Troy built trimmertb90bc starts but stalles in 5-10 sec,replaced fuil lines qnd bulb,but still stalls in 5-10 sec.

Hi,
Suggest clean the carb and using either a gasket and diaphragm kit or an full blown repair kit. Probabably a D-10WAT or K-10WAT in order afore mentioned.
Peace,
Clarke