Honeywell QuietCare HCM - Honeywell QuietCare HCM-630 Humidifier

Not clear on what you are working on

If you can locate a crack in the clear plastic tank, there may be a chemical you can buy to "weld" the crack closed. If you aren't sure what plastic it is, you might try sealing the crack with bathroom caulk that is mold resistant. You must locate the source of the leak and patch that.

The engine messed up.

remove and clean the filter then re-install it the air is being blocked

I am surprised that this answer isn't found anywhere, including in the manual from Kaz. If yours is the same version as mine, and your lights aren't even lighting up on top, most likely your float may have gotten bound up with gunk (the float rises up when the pan is full enough of water, which enables the motor to run. It is held into place by a plastic bracket with two phillips head screws, and looks a bit like a plastic bottle with a narrow neck in a small rectangular shape (not open at top). Remove the screws and the bracket, and take out the float and clean it and the reservoir (in the base) it sits in. Reinstall, and the float should move freely. Problem solved!

filter needs to be replaced

Found a hairline crack in the water canister. Had to locate by filling the canister and waiting for a couple of minutes for water droplets to form outside the canister. This ever so slight crack allowed air to enter the chamber and made changes to water dispensing rate which overfilled the resevoir over time ( hours). The cracks were not visible under 10X magnification without the water droplets.

It may not be large enough to bring it up depending on the size of the space. I would try hot water on pad, and maybe even boiling water as well as turning on a shower to get it up. Then use hot water to maintian it.

Poor design, buy a different brand, I have owned two, they are junk.

Look for a microscopic crack in the water chamber. Leaking air will allow the water to continue to drain out of the tank. A bit of glue and duct tape over the crack should fix it.