My Karcher K3.91 was searching and there was water being forced out of the detergent feed tube. I have cured the searching by disconnecting the mains water inlet connector and cleaning the inlet filter which was clogged with fine debris of some kind. The detergent suction tube is still emmitting water instead of sucking. I will try the backflushing technique and post a note if it cures the problem.

ossie davies, March 2011

Well done Ossie davies glad someone else posts a solution when they find one. Will be watching incase my Macallister does it.

Just a suggestion the cause may be build up of detergent some one told me not to use liquid soap for that reason as in car screen wash it clogs up the spray jets and eventually blows the pipe apart at joint on my rear one couldn't understan why I got showered throug trimming in roof each time rear screen wash operated took off the trim and pipe had come off joint fitting.replaced blocked tub a bugger of a job.

BB, March 2011