i own a few XP 215s, the marvel heroes pack, and one in the 2011 Nerf Super Soaker color scheme. Both my 2011 models (i have since lost one) performed much worse than the Marvel heroes ones - about a meter less range, with much more pumping required.
i opened up my remaining 2011 one and the problem seems to be the check valve - it slowly leaks air back into the pump - even at low pressure. I attached a balloon to the pump assembly and pumped it up - it slowly deflates and a whining noise is just audible. If i put my finger over the end of the pump tube it does not deflate and the noise stops - so there is no leak in the tubing it is definitely the check valve allowing air in the wrong direction
has anyone had similar problems with blasters before and can you recommend solutions to repair the valve?
only other thing i can think of is to replace the part but check valves are hard to get hold of and XP 215s are tiny so there is very limited space.