Trying to rebuild 18 hp Johnson

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

The drive shaft seal from a 18hp from 1958 through to the 70s should be as follows:

Part number: 321788
Sierra Part Number:18-2032
Shaft: 0.5"
Bore: 0.999"
OD: 1.003"
Width: 0.188"

Prop shaft seal from a 18hp from 1958 through to the 70's should be as follows:

Part number: 313284
Sierra Part Number:18-2005
Shaft: 0.625"
Bore: 1.124"
OD: 1.128"
Width: 0.25"

Is this what you have?

Yes the drive shaft seal measure's 1in outside. 1/2in inside and about 7/32 width. I don't really have a way right now to measure .188,but rough estimates puts .188 real close to 7/32. The hole that is left by the removed drive shaft seal is exactly double that .188 measurement. mm is as small as i can go the seal measures about 4 1/2mm and the hole left by the other seal is 9mm

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

http://www.marineengine.com/parts/j...odel=J6RCOB&manufacturer=Johnson?ion=Gearcase

different animal, but shows how to orient the double seals.

Well that's even more confusing as it looks like they have them mated top to top. Meaning the bottom of the seal would face correctlly ,but the top of the hole would have the second seal upside down with the bottom facing up. Of all the ways i thought I might do this that is not one. I would either just stack 2 exactly how they would go if i was putting in one or put them bottom to bottom with both tops facing outward

 

[nwcove]

Re: Trying to rebuild 18 hp Johnson

i see it as the open ends of both seals face each other, one closed end faces the top, one faces the bottom, or with the prop shaft, one closed face is towards the prop, the other is towards the gearcase?

 

[HighTrim]

Re: Trying to rebuild 18 hp Johnson

Actually no on those models the seals open end outwards. If you look there is a zoomed in bubble beside the drive shaft seal with an arrow pointing at the seals to show orientation.

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

i see it as the open ends of both seals face each other, one closed end faces the top, one faces the bottom, or with the prop shaft, one closed face is towards the prop, the other is towards the gearcase?

Ok well that's the way i thought I would do it, But it was hard for me to figure out the pics in the link. I think as of this minute that's what I'm going to do. Thanks for posting link,and helping. Hightrim ,and Kfa thank you guys too.

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Actually no on those models the seals open end outwards. If you look there is a zoomed in bubble beside the drive shaft seal with an arrow pointing at the seals to show orientation.

O Brother LOL... That's the way I took the picture too. Well I'm putting it together I guess when I get to the drive shaft seal we'll see.

 

[tosoutherncars]

Re: Trying to rebuild 18 hp Johnson

Take lots of pictures!! I'm probably going to have to do this eventually...

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

I'm on it sir. Fixing to load them up.

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Ok so here's my lower unit reseal kit,and lower unit rebuild. Hope I did it all right. For sure wouldn't have without the help of guys here on Iboats. So thanks guys

Kfa4303 recommended using sockets the size of my seals to drive them into place. So finding the right size sockets was first.
The first seal to go in was the shift shaft seal and O-ring. For it I just used the end of a 1/2 in dive extension. I put just a little Vaseline on the O-ring then started it in the hole. Next I put a ring of 3m 847 Gasket sealer that was recommended by Hightrim around the Shift shaft seal, and set it as straight as possible on the hole. Using a hammer and 1/2 drive extension lightly tapped it into place.

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[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 2.
Drive shaft seal. The drive shaft seal is one concern of mine. The only seal available for 18hp Johnson is about half the height of the original seal that came out. My lower unit reseal kit the Mallory one actually came with 3 seals the size that fits into the drive shaft housing. With 2 of those seals put together equaling the height of my original seal. So thats what I did I put 2 of those seals in my drive shaft seal housing making the seal come flush with the top of the housing just like the original. I put the seals in directly on top of each other so the bottom has what should be the bottom of a seal ,and the top has the top of a seal showing. The process was the same as the shift shaft seal. A little 3m 847 around the seals then hammering in lightly. I found it was a little easier using something a little smaller than the actual seal. so in my case I just flipped the 1/2in extension over and used the larger side to drive the seal in.

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[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 3.
Prop shaft seal and O-ring. The prop shaft seal is the same process no big deal. For the O-ring I added 3m 847 all the way around the slot that the o-Ring rides in, then slipped it on. As I was warned the 3m 847 is a sticky mess so be prepared

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[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 4.
Water pump and Impeller. to Instal the water pump first I took the drive shaft, and slid the water pump plate on from the bottom. The plate has to go on first because of the Impeller drive pin that sits right on top of the plate. then slide the drive shaft down thru the housing and into the lower unit. Making sure the plate is turned the correct way as mine would only line up correctly turned over one way

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 4 part 2
Water pump Impeller. Now slide the impeller down the shaft making sure to align the notch in the impeller to the drive shaft pin, and next the housing. In a service manual I have it says to oil the impeller blades slightly. Then push the housing down as you rotate the drive shaft clockwise to position the impeller blades correctly inside the housing. So I did this and it worked like a charm except for the fact that pushing down so hard made my bottom plate spin out of position. So sliding my fingers under the housing and Impeller I lifted both up and repositioned the bottom plate. Slid the housing ,and impeller back down. Applied 3m847 to my screw threads then screwed down the housing.

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[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 5
Shift shaft rod and Lower unit gears. I applied some Vaseline to the shift shaft rod and slide it from the bottom up thru the O-ring and seal. My lower unit gear had been out of the LU for about 2 and a half weeks so I had them double bagged soaking in some lower unit oil to prevent rust. I removed the gears from the bags. Spread a little gear oil on the prop shaft. Laid out all the gears then reassembled.

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 5 part 2
Lower unit gears reinstall. After assembling the gears. I turned the LU housing over, and installed the pinion gear. It just slides onto the bottom of the drive shaft. Then located the LU housing locator pins. Then the prop shaft gears alignment holes. Setting the prop shaft and gears on the housing ,and then rotating both ends till the holes dropped on to the pins. Then folded down the shift rod cradle, and I was almost done

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[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Step 6
The skeg ,pivot pin and oil screws. So I applied the 3m 847 all around the skeg in the groove cut for the spaghetti seal. Pushed the sill into place allowing about a 1/16 of an inch over hang on either side. Placed it over the lower unit gears. Then put some 847 on the screws ,and tightened them into place. The lower unit seal kit came with an O-ring for the Pivot pin, and 2 washers for the oil fill holes. I screwed in the pivot pin and o-ring. Then filled with gear oil, and placed the oil washers and screws into place.

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Well That's that let's hope it's right. My one question for you guys is should the drive shaft be really hard to turn by hand. Here's a before and after

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[AlTn]

Re: Trying to rebuild 18 hp Johnson

that new impeller makes it pretty stiff to turn in my experience....did you put any 847 between the bottom of the wear plate and gear box housing?...not sure it's necessary, but I do...if you can turn the d/s, now is a good time to ensure you have f-n-r before bolting it back up....thanks for taking the time to photograph and share your work!

 

[ccvolsdhf]

Re: Trying to rebuild 18 hp Johnson

Thanks Altn,and no prob on sharing...I think there's just enough play in that drive shaft to squeeze some under the plate without much hassle.....what is F-N-R

 

[Mas]

Re: Trying to rebuild 18 hp Johnson

Unbolt the water pump housing, slide it up, then see if it is still hard to turn. Then it should turn easily.

Mas