2006 Bombardier Outlander Max Series Factory Service Manual, Page 68Get this manual
Section 02 TROUBLESHOOTING Subsection 02 (TROUBLESHOOTING CHART)
SYMPTOM CONDITION TestInspection
ENGINE BACKFIRESNORMAL USE1 Check spark plugaCarbon accumulation caused by defective spark plug Rep lace spark plug2Chec leakage on intake manifold aAir leak on intake system Retighten screws andor replace intake manifold gasket