1977 OMC Gearcase Aluminum Alloy

[redneckgenius]

I need to do some welding on the gearcase of my 1977 OMC upper gearcase. The case is broken where it hinges on the intermediate housing on the starboard side. It's completely broke in two (im guessing from rough trailer rides and it got to floppin) and I feel good about being able to weld it, but would like to know if anyone knows what alloy OMC cast these out of. Thel boat is a project and I'd like to go this route as opposed to replacing the upper gearcase. Anyone have any experience or luck welding this type of break? Thanks in advance for the input.

 

[southkogs]

Re: 1977 OMC Gearcase Aluminum Alloy

That housing is not too hard to find out on ebay or with a couple of other "salvage" places (even donor boats off CraigsList). I don't know nuthin' about welding, but that seems like a high enough stress area that the original cast might be more solid.

 

[Boomyal]

Re: 1977 OMC Gearcase Aluminum Alloy

Sorry, I don't know about the metal composition but I can't imagine how a pivot trunion broke on that upper outdrive housing. That being said, OMC's are very particular about the parallel alignment of the pivots as well as the receptacles on the intermediate housing. They even have a special tool to check the intermediate housing alignment.

 

[redneckgenius]

Re: 1977 OMC Gearcase Aluminum Alloy

Thanks for the thoughts on this. A new gearcase was my first option, but i've had no luck finding one on ebay or CL. I've found some new ones for 1800+, but right now that's not feasible for me. This is on a project boat, so I may just keep looking till i do find one. Great forum with tons of knowledge, thanks again.