Merc 9.8 impeller shaft size?

[bblument]

I've got a 9.8 Mercury, ser# 6551122, made in 1984, and it's not discharging any water. A search for a water pump rebuild kit (or impeller, at least) turns up two different sized impellers for that era engine dependent upon shaft size... .438" or .456" i.d. I'd like to get the part ordered BEFORE disassembling the lower unit; even if I did disassemble it first, I don't have a micrometer to measure the shaft size anyway. Ideas? Thanks!

Barry

 

[Yegboats]

No sorry. 89981 or 89980 when you pull it off sometimes there is still the number between the impeller blades left on it. I can tell you that the 89981 is the more common of the 2.

 

[Scott Danforth]

you need to measure. if you want to order parts BEFORE, then you need to order both kits. I suggest getting a complete kit. while at it, get a grommet for the top of the water tube under the power head, and the grommets in the foot.

if you dont have a dial caliper (every mechanic should have one) use a 7/16" wrench. if it fits over the shaft, you have a 0.438" shaft. if it doesnt you have a 0.456" shaft

 

[bblument]

Thank you BOTH, very much. Very helpful. Best to you.

Barry