What impeller do i need for my Mariner 40 ML

I recently discovered that my mariner was a 1986, thanks to the help of people on this site. So i figured id ask for more help. My serial number is 40 ML 6E9 L 310423 which makes the model number a 7040226. Today i picked up a impeller from a local yamaha/mercury dealer and it is a 6F5-44352-00 part number and it is yamaha manufactured. I realize that yamaha made my Mariner and that a yamaha part will more than likely fit it but i believe this particular impeller is incorrect. Can somebody please verify which impeller i will need? Part # ? Thanks

99971M

Steve

Ref. No.Part No.QtyDescriptionComment1 9680M 1 GEARHOUSING ASSY (SHORT) -1 9681M 1 GEARHOUSING ASSY (LONG) -2 9573M 1 GEARHOUSING -3 83857M 1 PLUG -4 81924M 3 PLUG -5 81987M 3 GASKET -6 83392M 1 SCREW -7 95610M 1 GASKET -8 83883M 1 BUSHING, SHIFT CAM -9 82451M 1 BOLT -10 82214M 1 WASHER -11 82881M 1 BOOT, SHIFT ROD -12 83881M 1 SHIFT CAM (SHORT) -12 83882M 1 SHIFT CAM (LONG) -13 83396M 1 COVER, WATER PUMP -14 81426M 1 WATER SEAL, RUBBER -15 83403M 1 INSERT -16 99971M 1 IMPELLER -17 83398M 1 GASKET, WATER PUMP -18 83400M 1 FACE PLATE -19 83399M 1 GASKET, WATER PUMP -20 83864M 1 BASE, WATER PUMP -21 83865M 1 GASKET, WATER PUMP -22 82275M 1 O-RING