Darkside question

[bullie]

Don’t tell anyone, but I am working on a 9.8 Mercury for a fellow and I need some help. It’s running now but I need to find the part number for a water pump impeller and y’all know Mercury likes to keep things like that a secret unless you know the serial number of the motor. I can’t find the serial number but it’s one of the 9.8 hp "Thunderbolt Ignition" model years that required the small fuel line connector. I am hoping that it was a short enough amount of time that the water pump is the same for all years. Anyone know the part #?

[bob-d]

Just did one for a 1971 9.8HP Thunderbolt ignition. Here is what I used
Great motor when up and running.
Bob D

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[outboard315]

What color stripe. It looks like up to 1979 had one impeller and after had another. Also the serial tag should be on swivel.

[dave-bernard]

check the block for the serial ### if you have no plate. there were 2 Impellers early had a smaller driveshaft that is the only difference

[bullie]

Where the tag should be is a Mississippi Motor registration plate. I had no idea we ever had motor registration.

[bullie]

quote Outboard315:

What color stripe. It looks like up to 1979 had one impeller and after had another. Also the serial tag should be on swivel.

Red Stripe.

[outboard315]

Red stripe is 68-72 but it looks like as Dave said two different sizes. It’s either find the block serial number or measure the ID.

https://www.oldmercs.com/category_s/164.htm

[bill-russell]

If your impeller is a Mercury part it will have the part# molded into the side of the hub. It wil be 89980 or 89981 available from any Mercury dealer. Bill

[billw]

Like Dave said, there was a smaller diameter hub on some of the earlier ones, red stripe included. Going on memory but I think it is 47-22748? It’s the same one used in a Mark 6-type lower unit. Anyway, it is so different that there was even a different number for the power head stand tool, because the top splines were a different size. The 89980 and 89981 confusion came a little later, in the blue stripe, fiberglass cowl days. Those diameters are so close that a lot of times, you find someone has put the larger 89981, in place of the ’80 and it works, although not really correct.

Long live American manufacturing!

[bullie]

Thanks guys. I measured the ID and ordered #89981. It’s the larger one I think.

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