Hey KWIKR1,
You need to add a washer under each Snap ring so the rubber pulsator stay more secure. I took some photos of my New ATR double pumper that i have not installed yet. Hope this helps.
my pulsator rubbers were in pretty tight with just the snap ring , don't think I would be able to even get a washer in there without compressing the rubbers . not sure if that would be a good thing seeing the rubbers may have to be somewhat distorted to get the washers in . I even pressurized the whole assembly with about 60-70 psi of air to make sure everything stayed where it was suppose to . The only way I'll really know is when the car goes back in service next season . I think there maybe a few that have installed these ATR couplings without even any snap rings and have put them into service . I would like to hear from those who have .

I did pressurized the assemble without the snap rings and it blew the rubbers right out of the coupling on to and down the outlet necks of the pumps . so your saying ATR built these with washers and snap rings in ??? Please post pics .
