Johnson 120 Lower Ubit

Hey guys im new here , im in need of a lower unit for my 1985 120 johnson the numbers ive found on the transom are J120TLCO and also 7026334 just wondering if anybody has anything laying around collecting dust hopefully something i can just bolt on and go any info will be greatly appreaciated thanks guys john downes

Re: Johnson 120 Lower Ubit

i have the same motor the gear case on that unit is a v 6 gear case so if u can find a v 6 gear case u r set

Re: Johnson 120 Lower Ubit

Not quite. It's the size of a V6 but not the same. A normal V4 case will work just fine but you'll need another prop. You can put a V6 gearcase on but you'll most likely need another prop because of the different gear ratio.

Re: Johnson 120 Lower Unit

Re: Johnson 120 Lower Unit

so what other lower units will work for me ive heard rumor that evinrude is the same but what years and sizes, also what other johnsons

Re: Johnson 120 Lower Ubit

mr hadley can answer this beter than i can. that guy has forgoton more about these motors than i will ever be able to learn. but i will give it a shot the v 4 gear case and the v 6 gear case will bolt up to your mid section u just have to make sure they are for a 20 inch shaft i think that is what you have the v 4 and the v 6 have gear ratios that are taller and shorter than the one you have (the 85 120 is a weird duck) the v 4 and v 6 gear case will work on your motor u just have to re prop the boat because of the gear ratio
i would ask mr hadley if i am right on this just to be sure because i did not know the gear ratio was not the same. what is wrong with the old lower unit can it not be fixed

Re: Johnson 120 Lower Ubit

i am not sure what years but a evinrude will work

Re: Johnson 120 Lower Ubit

it can be fixed but im not sure i want to spend 1500 on a boat i only paid 2500 for

Re: Johnson 120 Lower Ubit

RB is right on. Any V4 gearcase from 1979 & newer will bolt right on as long as it's a 20" shaft. If you use one from a crossflow or a 60* you'll have to use your shift shaft. Obviously you'll need a V4 prop.

A V6 gearcase will also bolt on, again looking at the shaft length and using your shift rod. The gear ratio is different so you may have to reprop or repitch.

The larger V4 case like you have will also work obviously.

Personally if it were mine I'd take the opportunity to put a regular V4 case back on. Those larger cases allowed you to run a larger diameter prop but we have much better V4 props than we did in 1985.

There is at least one other small difference but it can easily be delt with later. Nothing that will stop you from going fishing.

Before we get too far look at the diameter of the prop you're running. And count the splines. Someone may have put a standard case on there already. The prop should be a 15 spline and 14 1/4" diameter if it's a V6 type case. The V4 cases are 13 spline and normally use a 13 1/4" prop. In fact just knowing the spline count will tell us what we need to know.

The one thing I gotta ask is -- what in the world happened that it's going to cost 1500 to rebuild this one?

Re: Johnson 120 Lower Ubit

Oh, you can use a V8 case too but I don't know why anyone would.......

Re: Johnson 120 Lower Ubit

look on ebay u can find several for under 750.00

Re: Johnson 120 Lower Ubit

yeah i found one on ebay for 600 probably gonna go that way,as for what i did i hit a rock bar and broke the drive shaft and bent the prop shaft this motor is on a 26ft pontoon