mid 70's 9.8 merc OB sn 6306408

[joemamma_222]

Hi all ! Just needing a little advise on an impeller for this motor ? Anyone might have the part number ? I noticed at Idle the water flow out the tell tale was sputtering. at mid range rpm the tell tale was nice and strong. (Hopefully I dont have any blockage). Anyway I've changed the impellers on higher HP mercs of the 70's but never one this small. Does anyone have any tips or tricks I can follow ? This is my dads motor and I just want to borrow it as a back up motor for my big boat when I'm on the Big lake. I know I need a manual but I dont have one at this time....

should I be in N when dropping the Lower Unit ?
Where would the shift shaft disconnect ?
by the way it's a 24" shaft.
Thanks for any advise !
Joe.

 

[WillyBWright]

Re: mid 70's 9.8 merc OB sn 6306408

It's either 47-89980 or 47-89981. Both are identical except for the center bore. 80 is a little smaller than 81. The shiftshaft is splined like the driveshaft. You don't need to disconnect it. Forward is Mercury's preferred method. I find that Neutral works better for me. Your public library probably has manuals.

 

[joemamma_222]

Re: mid 70's 9.8 merc OB sn 6306408

I dont know how I double posted this but I appreciate the Info. Glad to hear...I'll take off the lower unit tonight. I'm beginning to wonder what year this motor is now. cant we tell by the serial number ? I'm thinking I'll need to take the old one off to compare it to the new one before buying it ?

 

[joemamma_222]

Re: mid 70's 9.8 merc OB sn 6306408

Cool I jsut called napa and they have both part numbers....It;s on my way home...Wonder which one I should get ?!
10.99 for the Impeller....