20 Most Recent Hitachi NR90GC 3 1/2" Gas Powered Clipped Head Framing Nailer - Page 4 Questions & Answers

Take it back, fool with and you loose the warranty.

Disassemble the feeder mech and clean it... the grit in the cement dust will start to keep the parts from moving freely

You have an "O" seal leaking in there somewhere.

gas pattern valve ?

YES always replace the parts and keep safety for all if in doubt clean regulary the cilinder internally because its very thin These cylinders break easily if something is faltering. https://devs.hitachi-koki.co.jp/ois/explodedDiagram.html?type=svg&modelName=NT+65GS&newwindow=true

NV65AD3 or that kind of ? NV90AB2 on the biggest transparant plastic part that will fitt on the upper part and the squill will fitting in. with a well-fitting pipe wrench that fits just in the rounding so you can control it somewhat fix the upper part in a bench vise then push with the pipe wrench around 20 mm or maybe some bigger it to its place and with both hands you can push it on place, a plastic hammer is not allways necessary .

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Bad trigger switch(circuit board)

Sounds like a bent nose. It's been dropped

could be in need of an internal adjustment to stop the hammer from hitting the end plate ( travelling to far) talk with a tool repair shop and see if there is something that can be done contact a a hitachi service agent for advice go google and type in--- repair manual for Hitachi nail gun-- and see if there is a manual in pdf version that you can download

If it's new, return it. on warrant. If used, ask where you bought it, maybe they have some experience

oil it

lube the nails