Not with a Cummins but with my Cat 3208's. It's a lot easier than you think and in my opinion certainly worth while.. So much so, I intend to make this a yearly procedure. First remove the seawater input pipe to the raw water pump. Next remove the Impellar in the sea water, pump and close the pump back up. Next remove the sea-water out pipe that connects to the exhaust outlet. Get a big tub ( I used a plastic dustbin) and connect two pipes to the ports.. One to the seawater inlet pump , the other to the sea water outlet pipe... These two pipes go to the tub. The pipe that runs to the sea water pump (from the tub) .. You need to install some form of pump in-line. Next fill the tub with the BB concentrate and the correct amount of water and turn on the pump. In essence, the pump draws the concentrate from the tub, pushes it through the engine and the output goes back into the tub. Let this cycle for a couple of house and everything with be as brand new!. Refit everything back and it's a good time now to install a new Impellar. The product works fantastic. Highly recommend it!