TOPIC: Lower fin is broken off of the Mercruiser outboard

Lower fin is broken off of the Mercruiser outboard portion of the I/O. It looks like standard cast aluminum to me so can I take off the lower section and fab and shape up another fin and just TIG weld it on? Looks like a piece of cake but thought I had better check before I get something too hot or something. I hate surprises!

With no responses I decided to press on so I traced another fin from a good outboard and made a template. I then traced the broken fin edge after cutting it off in straight lines instead of the broke jagged edge. I matched the shape of the good template up to where it fit on the broken fin and traced the broken line onto the template. I then cut a piece 1/4" aluminum the appropriate shape and TIG welded it into place. I did fill the unit with water and used heat fence to keep the heat from moving north too far. A little sanding with the 4" sander and some black rattle can paint it looks like new.

Thats the way to do it. No problem.

We've done hundreds in my shop exactly that way. You should not have any problems.




!

Similar to how I did mine on my outboard. Only main difference, I drew it up in CAD and waterjet cut it!

I wasn't sure if there was any seals or gaskets I could ruin with the heat but it seems to be OK. I need to take it apart and inspect it as well. It hasn't been in the water since 85 so I'm sure a new impeller at least will be needed. The boat hour meter reads 518 hours. In boat years is that old and well used or ?

It totally depends on if "someone" left the key on until the battery went dead more than once.

Its a 1973. So thats 13 years used, and your in "always summer" county, so 40+ hours a year is nothing. BUT, hour meters say little of maintenance, but in your case that boat was well cared for, so forget about it!

Thanks guys... Starting to feel much better about this thing with your responses. LOL

I pulled the tanks and cleaned them out. Put new rubber hose on the tanks and sloshed in enough gas to light it off. Hooked up the earmuffs and primed the big arss fuel filter, Put a splash of gas in the carb, cranked a few times and she wanted to light off in the worse way... then nothing. No key action at all. I pulled off the + side of the battery and touched the post of the battery with it and sure enough there was a spark. Tapped the starer and no change then I remembered the solenoid is separate so I tapped the solenoid and guess what... I need to change out the solenoid now. LOL Oh well a small price to pay for sitting for some 28 year waiting for me. LOL