1974 Johnson 50 hp lower unit

[Oldone88]

I recently acquired a 74 Johnson 50 hp model # 50ESL74M. The engine will start and run, but the propeller shaft is frozen, and there was no gear lube in the bottom end. I removed the prop, and have been trying to remove the bearing support, but it seems to have welded itself in the housing. I've soaked it with aero kroil, put quite a bit of pressure on it with a cheap puller i have, and also applied heat at the same time, but no luck so far.

Im trying to determine if there are other drives that will fit this engine..

I measured the lower drive just now, and this is what i came up with. It measures approx 17" tall.. The shaft appears to measure about 21.5' It has 14 splines. There are 3 cooling slots w/screen on each side.. There are also 3 slots above the cavitation plate. The hub appears to be about 4", hard to measure precisely with the shaft still there.

Any assistance for the support removal is greatly appreciated.

Also any info about other year drives that may be compatible would be great.

Thanks

 

[jimmbo]

A drive from a 73 50hp should work as it has the same Design of Shift Mechanism, That's about it, the 71 - 72 used a different shift system, and in 75 OMC went to a Smaller Gearcase, whether the smaller case will work I can't say) Just make sure you get the proper length of Drive Shaft, as back then it was offered in both 15" and 20" models

Even if a case from a 1973 65hp or 74 70 hp were to bolt up, the Gear Ratio will be off. the 50 had very short gears 12:32 while the 65-70 had 12:29

You did remove the 4 screws that hold the Bearing Carrier? More Heat might need to be applied.

 

[Oldone88]

Yes, the 4 bolts have been removed. Going to try and find a better puller and then I will apply more heat.

Thanks for the info about the drive compatibility.

 

[racerone]

Well----The 3 cylinder 65 and 70 HP lower units are guaranteed NOT to fit because they have a different spline on the driveshaft !--------You are limited to a 73 and 74 50 HP for a direct fit.----The newer ones shift to FORWARD with an UP motion of the shift rod.----Yours shifts to FORWARD with a DOWN motion of the shift rod.----You would have to know how to compensate with linkages on the side of the motor block !!

 

[Oldone88]

Are the 73-74 Evinrudes, the same as the Johnson?

 

[racerone]

Different color paint on the lower unit.

 

[Oldone88]

just as a followup, i never was able to remove the bearing carrier. Heated it pretty hot and eventually pulled the threads out of the carrier.. Ended up buying a used lower unit, that was in pretty decent shape.
Thanks for the help and suggestions.