Mercedes Benz 280SE Auto (Model 126) Year 1983

I recently replaced the fuel hose connecting the bottom of the fuel tank
to the fuel filter. In the process, I drained out all the fuel.

Upon completion of the job and refueling, I could not get the engine
running normal. It could idle but hesitated upon acceleration. The
situation gets slightly better when the engine warmed up.

What could have gone wrong? Do I have to bleed the fuel pipes?

Please assist.
Regards.
YAHAYA