Bought a kicker... need a lower unit tho

[smokeonthewater]

sooo I picked up a merc 7.5 today serial number 4132901.
I'm trying to figure out what lower units will fit
Looks like the part number on my lower is IIRC 1630 3916 and I found a 1630 4407 for $50

 

[tazrig]

Re: Bought a kicker... need a lower unit tho

Not sure I understand the question. You bought a 7.5 hp Merc. Did it not come with a lower unit or are you looking for a different type of unit ie. long shaft etc.?

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

came with junk lower... looking for any lower that will fit .... would be short shaft.
If multiple part numbers fit then my search is easier.

 

[Blake0912]

Re: Bought a kicker... need a lower unit tho

I have a 9.8 around that same year as yours, mid 70's. I believe any 7.5/9.8 short shaft LU will work. If you can look for one newer than 1975 so it will have a stainless shaft the older ones are carbon steel. I just picked up one up off eBay with stainless shaft / new seals for $120 to replace my carbon steel lower unit.

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

and it fit? do you know the part number or year of the "new" lower you got?

 

[Blake0912]

Re: Bought a kicker... need a lower unit tho

Yes the lower unit fit just fine. My motor is a 1975 Merc 9.8 110, I'm not sure of the LU parts number I just found one that was a short shaft and bought it, it bolted right up. I read a few posts online and they all say the 7.5/9.8 LUs are the interchangeable as long as your shift shafts are the same length, mine is about 5in tall. But definitely try to find one with a stainless drive shaft if possible. The carbon ones usually have bad pitting.

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

hmmm mine has the 5" shift shaft too but the one I found is missing it's shift shaft... wonder if the shafts interchange as well?

 

[Blake0912]

Re: Bought a kicker... need a lower unit tho

From what Ive read the 1975 and up short shaft lower units should all be a 5in, if anything ask the person your buying it from to measure the shift shaft for you, it should be a spline with one flat side on it.

heres some pics of my 9.8 so you can kinda see what the LU looks like, I cant get you the part number over the weekend if your still looking by then.

I use mine for a kicker also, its a great little motor once I got the carb dialed in. Also have a 73 parts motor that I plan on sticking my old lower unit on to see if i can get it running.

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

can't have him measure his shift shaft because it's missing.... thx for all the info tho

 

[Blake0912]

Re: Bought a kicker... need a lower unit tho

I misread that sorry , but you should be able to put your shift rod on the "new" lower unit. I'd ask why there's no shift rod, did it corrode and break off or what? Be careful with the seals old the older lower units if it's carbon steel whith bad pitting good chance it would fail a pressure test. There's a few decent looking LUs on eBay right now but there $180ish. Anyways good luck with it.

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

pm on the way

 

[smokeonthewater]

Re: Bought a kicker... need a lower unit tho

update.. I bought an older 7.5 for parts... haven't run the numbers but I believe it was early 70's... had the aluminum cowl... Took the LU from it and swapped in my newer short shift shaft... bolted up and all was well. Thanks