1985 Johnson commercial 100 hp compatibility

[zorak]

Hi everyone. I need some advice. I just purchased a running 1985 johnson Commercial 100 hp VRO outboard #J100WMLCOC. This motor I think has a V6 lower unit on it (4-5/8" case diameter, please correct me if I am wrong) which corresponds with what little I have been able to dig up. My question is this. I wish to install power trim on this motor. I only have $100 into it right now. I can get a mid section, lower cowl, lower unit, trim control box and a few misc parts pretty cheap ($160) from a 1993 Evinrude 90hp #VE90MLETS . I can also get a "mid 80's" Johnson 88 hp with top & bottom cowl, Bad powerhead but most electronics intact, working trim, NO lower unit for $100. I am leaning towards the 90hp. Will my 100hp powerhead fit the 90 mid section or conversely, will the lower unit and trim off the 90 fit my 100 hp motor/midsection. Is the 88hp compatible? I read that the 100hp has lower compression heads so that"s why I am considering the 88.I know a lot more about mercury. This is my first evinrude/johnson. In this case, this is a time sensitive situation as I doubt either deal will be hanging around for a real long time so any help would be appreciated. Thanks!

 

[racerone]

Most of this stuff is all the same and can be made to fit.----Save for the crankshaft spline / driveshaft spline.-----But even that can be simply dealt with.

 

[zorak]

So, are the crankshaft splines different? I honestly don't know, and i have been trying to figure that one out as its a dealbreaker as far as I am concerned. I've looked at so many part numbers.

 

[racerone]

The spline shape / count is the same on all these V-4 motors from 73 to 98 models.-------They made slight change to the sealing arrangement of the spline O-RING on the crankshaft in the early 1990's.----It can all be made to fit if you know the wee details !

 

[Faztbullet]

That's the big housing with V4 gear ratio usually 2.3:1...do not confuse it with the V6 lower with 1.86 ratio

 

[zorak]

Ok. Thanks for the help. I will figure it out.

 

[zorak]

So, I believe I have the type O lower unit on my 100hp. I would like to buy the 90hp midsection/ lower unit and drop my powerhead on it, but I see that the johnson/ evinrude compatibility chart posted by Faztbullet shows there was a change in 1993, and the 90hp parts I am looking at are from a 93. I think that the driveshafts may be a different length as well.Not knowing squat about Evinrude, i have no idea how possible this is as the chart refers to "direct interchange". On the other hand, maybe I can just bolt the power trim onto the 100hp transom bracket. Again, I don't know if it's possible. Racerone made a statement about the o ring sealing arrangement being different. Again, i've never seen the difference. I have access to a metal lathe, and I do know my around machinery, but I'm asking for guidance as I just do not want to buy parts that can't be made to work. Thanks in advance for any help!

 

[zorak]

I don't know. It looks like a small v4. I may have been wrong about the diameter. Od isn't quite 4-5/8". Its hard to get an exact measurement with prop installed. According to what I have read, it should
be a type O

 

[racerone]

Instant identification.-----A small V-4 lower unit has a coarse thread for the prop nut.-----The V-6 lower units use a fine thread for the prop nut.

 

[zorak]

Ok, I will check.

 

[zorak]

It looks fine thread to me, but imdont have a frame of reference

 

[racerone]

Well ---Post a picture of the thread.

 

[zorak]

Pic posted