Nissan NS70A lower unit drive gear

[carlntx]

This is the drive shaft gear and spring out of lower unit on my 1986 ns70a. It looks like the spring broke and ate up the drive gear the froward and reverse gears still look good. I don't understand what that spring does or how it could break. but a piece got in the shift cam and it wouldn't go in froward. I understand you can't buy new parts for this old motor, but maybe someone has an used gear I could buy. I was having trouble shifting in froward about 15yrs. ago but it finally freed up and shifted ok until a few days ago when it froze up. I think its been running with those chipped teeth for the last 15yrs so if I can't find a gear I'll just put it back together and wait for it to blow.

 

[pvanv]

Re: Nissan NS70A lower unit drive gear

Very early models (70A2 up to serial 02052) had a 2-piece prop shaft housing (carrier), with a retainer. That spring looks like it may have come from one of those. It may have been put there by some mechanic as a "fix" for shifting, but does not show up any of my old parts catalogs. Perhaps your motor is older than an A2. True, the 353640200M BEVEL GEAR B is NLA. So your options are to either run it as-is, or locate a used parts donor motor. Elvin may have an opinion on your spring.

 

[carlntx]

Re: Nissan NS70A lower unit drive gear

Very early models (70A2 up to serial 02052) had a 2-piece prop shaft housing (carrier), with a retainer. That spring looks like it may have come from one of those. It may have been put there by some mechanic as a "fix" for shifting, but does not show up any of my old parts catalogs. Perhaps your motor is older than an A2. True, the 353640200M BEVEL GEAR B is NLA. So your options are to either run it as-is, or locate a used parts donor motor. Elvin may have an opinion on your spring.

The spring was on the drive shaft it set above the lower needle bearing. the way it was on the DS it looks like it would rotate with the shaft, which might be why it wore and broke. I'm just a shade tree mechanic so I can't see what the purpose of the spring was. As far as a mechanic working on the boat I've owned it since new and it's never been worked on.

 

[pvanv]

Re: Nissan NS70A lower unit drive gear

Some LU's had a "slinger" spring to lubricate the bearing immediately below the water pump. Maybe that's it.

 

[carlntx]

Re: Nissan NS70A lower unit drive gear

Some LU's had a "slinger" spring to lubricate the bearing immediately below the water pump. Maybe that's it.

You were right on it's an oil slinger I bought a used LU of Ebay took it apart to check gears and it had the same spring. My spring just looked like it was broken, but was made that way. I got lucky and all the gears are good on the used LU. I guess time will tell if it was worth the $400 To fix a motor whose parts are obsolete. The water pumps on both units looked good so at least I have spare pump.