Super Jet Midshaft Talk - Building, Rebuilding, SN vs. RN, etc.

Quinc

Buy a Superjet
Location
California
Anyone have a picture of the direction that each seal goes into the RN Midshaft housing? Is the last seal on the back of the housing brass out or rubber out?
 

JetManiac

Stoked
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Location
orlando
Anyone have a picture of the direction that each seal goes into the RN Midshaft housing? Is the last seal on the back of the housing brass out or rubber out?

Seals with springs go on each side of the bearing with the springs facing outward/away from the bearing.
The rearmost seal on the back goes with the brass colored ring facing outward.
 
Location
46236
Are you able to rebuild midshafts out of a 1996 Yamaha exciter jet boat that has 2 1100 triples or do you have a kit to supply other then WSM parts? (seems to be all I can find) Thanks
 

way2manyhobbies2keep

https://www.ebay.com/usr/way2manyhobbies2keep?_trk
Location
Sandy Eggo
May i add to the post my recent discovery about midshaft housings.
I found that most yamaha couches uses the "same" midshaft housing as SJ, just sitting on a larger bracket housing. See picture
View attachment 263351
You can unbolt this, press your SJ or custom midshaft in and mount it, ride and be happy. But what i found out, is while it appears to be identical, the internals has changed a bit, only running single double lipped seal in the rear (sj runs 2 seal, 1 single lip and 1 double lip in rear)
This could cause some confusing (it did for me) :)

Superjet:
View attachment 263352

G/QUOTE]

@JetManiac this oem diagram messes with me, it shows 2 of the same seal going in the back and 1 seal of a different number in the front, this I feel contradicts your instruction. Help me out here.
 
I know this is an old thread, but for the record, I just noticed that the 91 parts diagram puts the single lip seal 93101-25m53 on the water side and the double seal just inside of it (where 7 is in this diagram) 93101-25m52.

Chris I will be contacting you soon for a new housing as my 91, although bearings seem fine (no play), is quite corroded and believe is starting to leak through the rubber dampner. By chance is there a way to retrofit a newer (larger) housing version?
 
Location
dfw
Yamaha used an odd seal, i just use two cheap ones on the aft side. You will have to make an adapter plate or drill holes and install inserts to fit a 4 bolt carrier. The small ones are fine. They fail because corrosion gets between the rubber and metal. Salt water and/or poor storage is usually the cause.
 
Good to know they are o.k. I sold my SJ about 5 years ago, and am resurrecting this one that I bought a year or so ago and has sat on sat on my patio since. After this past weekends ride, I wonder why I waited so long:). Have been fishing off a GP in the interim and forgot how tossable standups are! .lol
The coupler looked pretty bad before dropping the motor in, but I was cheap and decided to give it a go anyway.lol. Chris or anyone out there have a good small housing or complete housing shaft (I don't have a press) (90-93)? Preferably with a 701 shaft.
 

JetManiac

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orlando
I know this is an old thread, but for the record, I just noticed that the 91 parts diagram puts the single lip seal 93101-25m53 on the water side and the double seal just inside of it (where 7 is in this diagram) 93101-25m52.

Chris I will be contacting you soon for a new housing as my 91, although bearings seem fine (no play), is quite corroded and believe is starting to leak through the rubber dampner. By chance is there a way to retrofit a newer (larger) housing version?

For the record, whichever diagram you are looking at is incorrect. You can look at any oem SJ midshaft assembly in person, and see which seals are in which position. It makes logical sense- the double lipped seal is facing then water in the most exposed position and has no exposed spring to get damaged. The inner and bilge facing seals are not exposed to the same extreme conditions.
 
Chris,
The diagrams were the ones posed on boats.net. I didn't check to see if the part numbers were actually the double or single. If you are right (i'm sure you are) then the they must be using the same double lip seal on the inside (motor compartment bilge area side) of the early models, as the diagram shows that as the same seal. The diagram I am attaching shows#7 is the same part as #10 (both are the m53's). Can you confirm m53's are the double lip seal?

I never contacted you as I couldn't pm (was to new) or find your or Pavis phone number in my past texts. I then ended up realizing that the leak was coming from the rear exhaust seal on the back of the hull and a leaky flush tube as well. Its dry now. I should prob replace the midshaft anyways, as mine is extremely corroded on the outside.
 

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JetManiac

Stoked
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Location
orlando
Chris,
The diagrams were the ones posed on boats.net. I didn't check to see if the part numbers were actually the double or single. If you are right (i'm sure you are) then the they must be using the same double lip seal on the inside (motor compartment bilge area side) of the early models, as the diagram shows that as the same seal. The diagram I am attaching shows#7 is the same part as #10 (both are the m53's). Can you confirm m53's are the double lip seal?

I never contacted you as I couldn't pm (was to new) or find your or Pavis phone number in my past texts. I then ended up realizing that the leak was coming from the rear exhaust seal on the back of the hull and a leaky flush tube as well. Its dry now. I should prob replace the midshaft anyways, as mine is extremely corroded on the outside.

Look at the pic's in Flave's post above for the seals orientation. Just send a PM to us if you need help.
 
Thanks, but would have you do the seals anyway. I'll hit you up when I have a list of everything for the ski I will end up needing. I think this weekend the ski gets pulled back apart and flipped so I can do some glass work for the handling followed by paint and graphics.
 
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