The injectors can be cleaned in one of those ultrasonic cleaners that jewellers use. My wife has one (she's not a jeweller, so what does that tell you?). The spray pattern, pressure at which they open and whether they leak, can be checked with a fairly simple tester and takes only a minute or two per injector. It's worthwile to have this check done every couple of years. The injectors are available new for around $100 a piece.
P.s. neither the injectors, nor the non-return check valves in the Fuel Injection pump body should leak. If they do, starting will be more difficult and the pump will be constantly trying to build up the necessary pressure in the line(s), rather than all of the pressure being applied to force the fuel into the engine. Whether you have a faulty injector or check valve can be checked I believe by simply undoing the lines one by one at either connection with a cold engine - if fuel does not immediately flow out under some pressure, evidently there was no pressure. Not 100% sure about this though, mostly conjecture.
Cees Klumper in Amsterdam
'69 white 280 SL automatic
