1957 Johnson 35HP RDE-19 Lower unit case shot?

[oldfarmall]

Hello-

I picked up a 1957 Johnson 35HP model RDE-19 for $75.00. Motor runs great, really moves my 14ft boat! Anyway, I pulled the lower unit off yesterday to install a new water pump impeller, housing, and plate. 2 of the 3 screws holding the pump in place came out, the third snapped off, so I have to fix that. My question is, when I pulled water pump, parts of the aluminum casting under the water pump plate were bowed out and cracked, and the water pump plate was warped. I attached 2 pictures of the casing. The problem areas are right above casting number under water pump and the upper left area that looks bowed in towards driveshaft hole. Also, found that this lower unit appears to be from a 1956 or 1955 Johnson, as the pinion gear and bearing do not look like the ones in my 1957 parts book. The casting number is 375769 for the lower unit. Can anyone verify years that used 375769 lower units, I am guessing 1955-1956 by looking at parts books, but the numbers are not the same. Will anything be affected by using this casing as is, or is the casting junk? Also, the bronze bushing below the water pump driveshaft seal appears to have spun in the lower unit casting, as it came out by hand, I thought these were press fit. If I have to look for another lower unit, what years are compatible? 1957-1958 only? I also read that the pinion gear in the older 1955-56 lower units were a weak point, and they beefed it up in 1957. Let me know your thoughts on this lower unit. Thanks in advance for any thoughts!

 

[F_R]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

The bent aluminum webbing under the pump plate should not be a problem as long as it is not cracked to the outside to where air can get in. The plate must be sealed against outside air and/or exhaust. I guess you know that freezing caused that.

You are correct, that is a 25-30hp gearcase, with the Timken Tapered roller bearing. Running 35hp on it is pushing the envelope, but it seems to have stood it so far.

The bushing is a slip fit.

 

[samo_ott]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

Great engine. I'd snap it up also for $75. It's hard to see what's wrong in your picture. Below the water pump does look a tad mangled but I cant really comment as it's hard to see. The skeg looks ok but it is also was hard to tell. Yes, the bushing should be pressed in. Never heard of one spinning out before. Weird. I'm not sure of all the LU years but the later 28's and 33's that were not the super quiet model will also fit I believe as I am doing a similar swap this summer by putting my '62 28hp LU on my '56 30hp as I've been told it would fit and I fully expect it to also. I have the parts manuals for the other years if you want to compare. If you want em, send me a PM with the model #'s you want and your email address.

 

[oldfarmall]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

F_R-

Thanks for the reply! I had a hunch that water froze after looking at the webbing. Is there any way to prevent water from freezing in the lower unit, other than bringing the motor inside in the winter? Shouldn't water drain out or evaporate? Is there any known way to repair the webbing, or is it probably not worth my time and I should just look for another correct lower unit for a 35HP? Thanks!

 

[HighTrim]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

As Frank stated, the webbing should be fine. If it makes you feel better smooth the cracks with some JB Weld.

The bushing just pops in and out on the 30hp. No problem there.

One of the problems with freezing is that the drain hole is plugged not allowing it to drain properly. Little critters like to nest in it. Be sure that it is free before bolting her back up.

Funny I have a 1956 30hp Johnson on the test stand right now that I am restoring. I too broke a water pump housing bolt. Take your time with it and do it right before you cause yourself a nightmare! My webbing was also cracked, you sure you dont have mine? lol

 

[oldfarmall]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?







Thought I would post the picture of the water pump webbing that is bowed with some arrows to the problem points. My camera does not take good close up pictures.. Thanks!

 

[oldfarmall]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

Hi-

Thanks for all the response on this lower unit. Another question, will the newer lower units, say 1959-up, work with my 1957 35hp motor since they have the dual outlet water pump? My 1957 motor has the single outlet pipe. What I am asking is: will the old style single outlet water pump bolt up to the newer lower unit casings and function correctly by simply using the impeller housing, impeller, and plate from a 1957 model? I believe the rest of the lower unit will bolt up like normal to the rest of my motor and skeg? Also, are the gears and prop shaft the same, with exception for the pinion bearing setup? Thanks!

 

[F_R]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

The dual tube lower units are NOT the same. They will not bolt up. And even if they did, the water pump is different. Teh gears are different.

 

[F_R]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

BTW, the Johnson Factory service manual sez the drive shaft bushing was cast-in up through the 1954 models, and was not replaceable. 1955-up had a replaceable FLOATING bushing, which was changed to a pressed-in needle bearing during the 1962 model year.

The floating bushing has oil holes and a groove around the O.D. to supply oil to the spinning bushing.

That's my story.....

 

[oldfarmall]

Re: 1957 Johnson 35HP RDE-19 Lower unit case shot?

BTW, the Johnson Factory service manual sez the drive shaft bushing was cast-in up through the 1954 models, and was not replaceable. 1955-up had a replaceable FLOATING bushing, which was changed to a pressed-in needle bearing during the 1962 model year.

The floating bushing has oil holes and a groove around the O.D. to supply oil to the spinning bushing.

That's my story.....

F_R-

Thanks for that info, that explains the floating bushing. So after getting great info from everyone, I will need to find a lower unit from a 1957 or 1958 johnson/evinrude 35hp to make my motor correct, or fix my current lower unit which is from a 25 or 30hp with the weaker pinion. Let me know if I missed another horsepower option that would work.

What exactly would be the weak point if I reuse the old style pinion lower unit? Is it the bearing and pinion gear that fails, or the casing if I am using on my 35hp? Thanks again!