Corroded Yamaha 30hp Lower Unit... Repairable? Cause?

[scout-j-m]

I bought this lower unit off of a 30hp Yamaha 3 cylinder a couple weeks back in hopes I could repair it. As the pictures show, it has serious corrosion plus possibly some other kind of damage in the area behind where the trim tab anode goes. There was also no fluid in the lower unit but it does turn the prop shaft as I turn the drive shaft by hand so it's not frozen up. I tried pressure testing it but it was blowing air out of the shift rod seal at the same rate I was pumping it in. Before I do too much else I was wondering if the corroded area can actually be repaired. It's not in the gear housing nor in the exhaust area which seems like a good sign. To be honest I was thinking it may could actually be ran as is assuming the gearcase can be sealed back up properly and function as it should. Does anyone have any insight as to what may have caused this? It seems strange to me that it can have that serious of corrosion in one location but be relatively corrosion free everywhere else, especially around the water pump where I often see some.

 

[racerone]

On more than one occasion have I seen corrosion damage like that on Yamaha motors.----Cheaper grade of material I believe.------Or perhaps brackish water.

 

[scout-j-m]

On more than one occasion have I seen corrosion damage like that on Yamaha motors.----Cheaper grade of material I believe.------Or perhaps brackish water.

Yeah this came from a guy who bought the parts motor locally around Houston, Tx so it is near the gulf so most assuredly has seen brackish water at the least.

To be honest, I'm not too concerned about that corrosion. Once I get it cleaned up and get the shift rod sealed up, I'm wondering if some new fluid and a new impeller may be all it really needs. I'd like to fix that area at some point, but if it isn't critical I think the only issue there is just keeping the corrosion from worsening. I'm in 100% freshwater myself.

 

[Sea Rider]

Seems the previous owner used that motor in saltwater for a long time period without the lower leg's anodes installed ?

Happy Boating

 

[tblshur]

Looks like to me someone used torch to get a bolt out and got it too hot :joyous:

 

[scout-j-m]

Looks like to me someone used torch to get a bolt out and got it too hot :joyous:

Yep lol. I did think it was odd that it looks like it took heat to get the lower off but that the drive shaft and water pump area are so clean.

 

[robert graham]

Fill holes with JB Weld, sand smooth and paint.....