1999 Sea Doo Challenger 1800?

Every spring when I want to start the engines, the "keys" do not make contact. I clean all the dirt, film, etc. from the inside of the key and the outside of the plug on the dash, but that did not help. Today I got several very short beeps that made the gas gauge needle jump, but then nothing. Battery is fully charged, no fuses are blown that I can find. Shouldn't you just be able to push the key on the plug and fire it up? Very frustrating.