74' Mercury 110 9.8 Lower unit Interchange

[Dbishop3]

I have a merc 9.8 ser#3926555 1974 year short shaft. I am needing a lower unit and am wondering what years would interchange with this. I know some guy that had a couple sitting around but i wanted to figure out what year would work before I drove over/offered him a price. Any Information would be greatly appreciated. Ive looked and found no such info. Thanks

 

[jbjennings]

Re: 74' Mercury 110 9.8 Lower unit Interchange

If I were you, I'd try for a '76 or later unit so you'd get the stainless drive shaft with it--your unit has a mild steel driveshaft which is the most likely reason you're needing a new one.
JBJ

 

[Dbishop3]

Re: 74' Mercury 110 9.8 Lower unit Interchange

Well the guts are fine its the housing is what im really needing. The prop hub wasnt centered and chewed the housing threads up. I think i could get it apart but going back together i think its done for. But if i could get a complete lower unit to work i would just switch them out. Your help is appreciated

 

[mercuk]

Re: 74' Mercury 110 9.8 Lower unit Interchange

If I were you, I'd try for a '76 or later unit so you'd get the stainless drive shaft with it--your unit has a mild steel driveshaft which is the most likely reason you're needing a new one.
JBJ

^^^ What he said is spot on...

But pretty much ANY 4hp, 7.5hp and 9.8hp gearbox from 1962-1986 will work. The only thing to be careful of is some of the SHIFT shafts were the same length than the DRIVE shaft on some models which are harder to get hold of, but generally these were the older models.
If your shift shaft is about 5" then it's the later version and as such, easier to obtain especially as JBJ mentioned with the stainless shafts. Good luck, there great engines and it's worth trying to find a good gearbox to get her up and running again.

 

[Dbishop3]

Re: 74' Mercury 110 9.8 Lower unit Interchange

Yep the motor runs great. I just invested some money in it replacing the sector gear, water pump,fuel pump, carb kit, and a new 3 blade prop. We dont have any 10 hp lakes around anymore but i hate to let the motor sit around ant not be used. I noticed the prop shaft seal starting to leak and wanted to replace but this is where i need to find a new lower unit. Due to the housing threads muffed up. Id like to get a spare motor for parts anyways. THe motor this guy had doesnt run but is complete. Any idea what i should offer him for it???

 

[mercuk]

Re: 74' Mercury 110 9.8 Lower unit Interchange

Yep the motor runs great. I just invested some money in it replacing the sector gear, water pump,fuel pump, carb kit, and a new 3 blade prop. We dont have any 10 hp lakes around anymore but i hate to let the motor sit around ant not be used. I noticed the prop shaft seal starting to leak and wanted to replace but this is where i need to find a new lower unit. Due to the housing threads muffed up. Id like to get a spare motor for parts anyways. THe motor this guy had doesnt run but is complete. Any idea what i should offer him for it???

Sorry I'd only know a value in ? sterling.....

 

[jbjennings]

Re: 74' Mercury 110 9.8 Lower unit Interchange

Those lower units require shimming and such to get back correctly if I recall, so be careful about mix-matching parts. If possible, I'd find a whole lower unit to switch. I believe the 7.5hp lunits will work o.k on your 9.8, but I don't think the 3.9 and 4 and 4.5hp lower units will;----I could be wrong, though!@
jBJ