What was found
STRONG CHEMICAL SMELL IN COCKPIT WHILE IN FLIGHT. PERFORMED TSM71-00-81-810-805-A THRU STEP4.A, 3, L HAS BEEN COMPLETED THE FIRST 4 ITEMS-NO TROUBLE NOTED. BOROSCOPE OF IP OVERPRESSURE HAS BEEN ACCOMPLISHED ON 1 AND 2 ENGINES-WAITING FOR RESULTS AFTER PICTURES WERE SENT TO PROPULSION ENGINE. PERFORMED BSI IAW AMM 72-00 FOUND STAIN ON NR 1 & NR 2 ENG AT IGV BETWEEN IP 3 AND 4 AND STAINING ON NR 4 IP AWAITING PROP OPS. PERFORMED CONTINUATION OF TSM 71-00-81. RAN BOTH ENGINES AT M T P NO ODOR ABNORMALITIES NOTED IN ALL CABIN ZONES. ENGINEERING EVALUATION OFF STAINS FOUND ARE NOT CAUSE OF ODOR. ACFT OK FOR SERVICE.