LOW SPD ABORT IN A B737-400 WHEN TKOF WARNING SOUNDS ALERT.

Narrative

DELAYED ON GND FOR FLOW TO EWR. TAXIED TO HOLDING AREA NEAR TKOF RWY 28R. AS OUR EXPECT 'WHEELS UP' TIME APCHED. STARTED #2 ENG (WHICH WAS SHUT DOWN); COMPLETED CHKLISTS; AND CLRED FOR TKOF IN A SHORT PERIOD OF TIME. AS WE TAXIED ON THE RWY; TKOF CONFIGN WARNING SOUNDED. AFTER QUICK CHK; WE DECIDED TO TAXI OFF RWY AT FIRST EXIT AND TAKE OUR TIME TO FIND THE PROB. THE CAPT MADE A QUICK PA ANNOUNCEMENT WHILE I TALKED TO THE TWR. UNFORTUNATELY; TO NOTIFY THE TWR; I USED THE WORD 'ABORTING.' WE TAXIED ONTO THE TXWY AND MADE A CHK. THE FLAP LEVER WAS NOT SECURELY IN THE FLAP 5 DETENT. AFTER RESETTING THE FLAP LEVER INTO THE DETENT; THE CONFIGN WARNING WAS SILENT. WE TAXIED DOWN FOR A NORMAL TKOF. AFTER HUNDREDS OF TKOFS; TO NOT IMMEDIATELY SEE THIS SEEMS UNUSUAL. THE FLAP LEVER IS NOT EASILY VISIBLE FROM THE CAPT'S SIDE BECAUSE THE THRUST LEVERS BLOCK HIS VIEW. THE TKOF WARNING DID WHAT IT WAS DESIGNED TO DO; AND WE PULLED OFF AND TOOK CARE OF THE PROB AS WE WERE SUPPOSED TO DO. THE MAIN THING I COULD HAVE DONE IS TO HAVE JUST ASKED TO TAXI OFF THE RWY AND THEREFORE NOT DRAW ATTN TO THE SIT UNNECESSARILY. ADDITIONALLY; A CONFIGN TEST SWITCH TO CHK CONFIGN PRIOR TO PULLING ON THE RWY SHOULD BE INSTALLED AND A CONFIGN CHK ADDED TO THE CHKLIST 'LINE ITEMS.' SUPPLEMENTAL INFO FROM ACN 343185: FO USED WORD 'ABORT' TO PIT TWR; BUT WE DIDN'T 'ABORT' SINCE WE WERE NEVER ABOVE TAXI SPD AND CLRED RWY EASILY. (NEED TO HAVE WARNING TEST SYS.)