...unscrew the thingy with the two wires sticking on the end of the red canister? I need to replace the extinguisher hangin over my Yanmar. Rather not stick my head in there and come back out covered in white powder (too much like my college years).
You don't say the model of your fire suppression system, but since you own a Hunter 41 DS I'll wager its a Seafire system like on my H36. If so, you'll need to figure out which model, but here's their website where you can download the manual which includes servicing instructions.
This seems to indicate that those wires are for an indicator light, not an actuate. But as noted above, we don’t know for sure what unit you have...use with caution. This is from the Sea-Fire manual posted by @tfox2069 above.
Man, don’t ever breath that stuff if it is used in a fire. It can produce Hydrogen Flouride, some of the worst of the bad stuff. It’s boiling point is 2.5f so it’s a gas at room temp. ( going off the Seafire post)
I believe that the ignition system needs those wires connected together after removal from extinguisher as they are meant to prevent starting the motor if the extinguisher pressure is low. Some motors/extinguishers had a manual override button that could be pressed when necessary.