75 hp flying scott gears stuck

Joined
Apr 27, 2014
Messages
23
Okay that may not be an accurate title but I am having problems assembling my lower unit and pump housing on my 75hp Scott motor.



I have not ran it and this is about how I received it. I added new driveshaft needle bearings but that's it. Everything turns fine in each gear as it should until I tighten the bolts holding the pump housing and the LU together, the they both essentially lock up. When there is a 1/32" gap they turn fine but when the gap closes it gets more tight.


What is happening when I tighten that last hair down? What can I be checking?

Thanks
Tyson
 

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,239
Welcome to the iboats.com forum! The members here are great and the experts, which I am not, can help you solve any problems with that classic old motor. I have a warm spot in my heart for the Flying Scotts because I did a lot of skiing behind one when I was a pup. However, I do not a clue about what you should do to fix the problem. Hopefully, one of the gurus will post into your thread and educate both of us. Do you have a service manual? Good luck!
 

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,239
Are you describing an "Owners' Manual" or is it a service manual with specs, diagrams, capacities, etc.?
 
Joined
Apr 27, 2014
Messages
23
It's the service manual, an original one. It's pretty descriptive on disassembling and putting together the lower unit and pump housing but when it says to torque to 23 inch pounds I can't. Not sure why the pinion gear and bearings won't go down into the gears...
 
Joined
Apr 27, 2014
Messages
23
No Title

Here are some pics. Do you think it's possible the pinion bearing is not down far enough? If so will I destroyed it by tapping on it?
 

Attachments

  • photo223312.jpg
    photo223312.jpg
    100.7 KB · Views: 0
  • photo223313.jpg
    photo223313.jpg
    86.9 KB · Views: 0
  • photo223314.jpg
    photo223314.jpg
    80.3 KB · Views: 0
  • photo223315.jpg
    photo223315.jpg
    86.5 KB · Views: 0

Willyclay

Captain
Joined
Sep 8, 2006
Messages
3,239
Thanks for the pix. I found some info online and there seems to have been two very different gearcases for that motor, a standard unit and a high-performance unit referred to as "Custom". Also, I saw references to ten "special tools" just for the lower unit. Does your factory service manual provide that info?
 
Joined
Apr 27, 2014
Messages
23
okay i got it fixed now, turns out the bushing and the bearing were not far enough down the drive shaft. It took a lot of hard whacks to get it closer to the pinion gear. Not even sure how it managed to work its way up there.
 
Top