increasing the battery amps to fit a water pump
I do not know where you got the 0.036A number for the Yuasa YB3L-B battery. Batteries of that type and their equivalent replacements are rated for 3 Amp Hour.

With a fully charged fresh battery you should be able to easily run the bilge pump for an hour or more as the pump drawing 1.8A is less than Amp Hour rating of the battery.

If your battery is only delivering 0.036A then it is either not connected to the load correctly or the battery is completely kaput and needs replacement with a new one.