Question about OMC 165 upper

[southkogs]

I need some help understanding something about my upper. Here are some details:

Boat: 1972 Silverline Comoro Tri-Hull
Engine: 1972 OMC 165 (Chevy inline 6 250)
Drive: 1972 OMC Electric Shift Stringer
Mechanic: 1970 model - "iffy" at his best

I've been dealing with an issue all summer long, and had the boat into the shop. Mechanic had it for six weeks (long story for another post - but I was traveling a lot, so it's a wash), and his final suggestion is that my upper is locked up.

I've posted on the original problem before, but for the moment I need to understand (before I go buy a new upper) if the drive is installed on the boat, and the engine is running (no grinding noises) - can the upper be locked up?

With the ball gears engaged, that upper is spinning correct? If it were "locked up" then the system would not even start - am I understanding that correctly?

 

[Howard Sterndrive]

Re: Question about OMC 165 upper

if the drive is installed on the boat, and the engine is running (no grinding noises) - can the upper be locked up?

no

your analysis is correct. your "mechanic" is out to lunch

 

[southkogs]

Re: Question about OMC 165 upper

As always Howard - you're pure gold. Stay tuned. I'll probably have more questions to follow on this one.

 

[southkogs]

Re: Question about OMC 165 upper

Perhaps need to start this in a new thread, but here goes anyway...

Grabbed the boat, and looked at the upper gear case. The top of the shaft is sheared off - literally the very top just under the access cover maybe a total of 2". Otherwise, I think it's moving fine.

I have another upper that is in pretty rough shape, but grabbed it intending to start the process of rebuilding a second outdrive. How crazy is it to try to rebuild an upper gear case, and what are the potential pitfalls for a noob like me?

 

[Howard Sterndrive]

Re: Question about OMC 165 upper

there are special tools to rebuild an upper. I don't see why it can't be done old school with prussian blue, a set of shims and rolling torque, but no manual shows that method. If you have rebuilt a lot of differentials and such, could probably tackle it. But if you shim it wrong, potential pitfall is swift destruction of the gearcase first trip out.

 

[southkogs]

Re: Question about OMC 165 upper

potential pitfall is swift destruction of the gearcase first trip out.

Thank you for saving me from myself

I'll go the safe route for now and try to find something to replace it.

 

[southkogs]

Re: Question about OMC 165 upper

Update - I think I've found a drive up in Michigan. Seller says it was rebuilt a few years ago (he's a service manager at a suburban Detroit auto dealership - and allowed me to contact him at his office which gave me some added confidence), but it is currently not on a boat. I'll be up there visiting for the week and plan on taking a look at it, but I won't have any way to hook it up.

Any advice on how to evaluate this drive?