When I hit the trigger it shoots - Hitachi NV45AB2 Roofing Coil Nailer

Trigger mechanism is fubar and needs attention. Replaceable?

Sounds like the trigger is sticky. Shoot a little bit of WD40 in the moving part in the trigger. . Not a lot but see if that loosens it up.

Best practice is to bump fire the gun to prevent double fire. Do not place the gun on the work and pull the trigger. This takes practice while using at an angle. Works better if the nose piece has rather sharp points to help nose to stay in postion while you bump. With trigger depressed, practice without nails bumping/hitting wood at different angles untill you can bump hit at the spot that you need the fastener. If the gun double fires while bump-firing, most likely all the safety/trip parts are worn/loose. Not expensive to replace. Good luck.

Worn trigger and or worn firing valve. Remove the trigger and look for wear on contact surfaces (worn pin that holds trigger, worn inner lever inside trigger, worn or loose firing pin in valve ). Easy test for worn trigger. Remove the nails, remove trigger, fire the gun against wood with finger to test for proper action. If it works better without trigger, consider replacing trigger with new (I would also order the oring repair kit that includes the firing valve )

Check the instructions for cleaning and lubrication tips. Sounds like you have a buildup of the adhesive that holds staples in "sticks," and it's keeping the staple stick from moving forward into the firing position.

You may need to adjust the trigger with the allen screws. One screw comes up under the
trigger and the other is straigh in line (you can see that one). Also, make sure you got the grips on right and didnt pinch or pull a wire loose( I did!). Will it fire with the eyes off (press the on/off once after power up to get to eyes off mode)? You should be able to see the magnetic part of the trigger as it moves toward the switch point inside the grip-frame. Is it traveling far enough into the frame to hit the switch area?

N88rh uses a full round head plastic collated nails which are spaced apart enough that the driver cannot hit two nails at once. If your are using other nails that fit into your magazine that are closer together you may in fact drive two nails at once. If, however you are using the correct nail and the nailer shoots twice, then you probable have a very sensitive firing valve. You could change the TVA6 valve or change the actual trigger. To overcome this problem of double firing and you do not want to try changing the firing valve, you need to change the trigger to sequential type instead of bump fire type. This trigger is usually white and will only permit one nail to be fired. Check www.toolpartsdirect.com or bostitch.com for parts. Good holiday

Most nailers work better by bump firing the gun. Less likely to double fire. This is a common problem amoung brands. If you place nailer on work then trigger, you may/will have problems as you describe. There is usually an option of triggers or builtin method of single firing the gun. With single fire trigger, you can place gun on work and fire. The will not reset for next round untill you let go of trigger and lift gun off the work. If your gun is double firing even with bump method, then replace the trigger valve.

Up inside the trigger is where the safety hits, it moves in the way of the trigger to get it to fire, but it has to hit something in between, i have the same gun, only older, and I deactivated the safety so I could get in tight spots. You should be able to see what is stopping it from moving, then see if the part is bent, broke, missing, whatever. I don't recommend disabling it. But you want to get it going. Hope this helps.

the 601 had a design flaw, in the nose, where the nails hit as the are being pushed forward, the peice was made out of a peice of metal that was too soft, it wore down and that is where you get the double nail problem.

Senco offered a trade in, this was years ago, for a limited time and gave us credit towards new guns, which we gladly did