Seized lower unit bolts 40hp

[thewillhartleys]

So I had to replace water pump and noticed bolts were stuck. Long story short, I did everything I could not to break them but I did. All six of them. Tried drilling out two studs that were broken off to no luck. Four studs still salvageable with 1/2 inch of threaded stud. My question is, should I try using left handed nuts to possibly remove the other 4, and would 4 bolts holding it on, be ok? What is the stud size and thread for said nut? Or should I just find a scrap upper casing and swap everything out?

 

[Sea Rider]

If it were my motor would take it to a machine shop and have them professionally removed if now is possible. That's a delicate part that needs to be well taken care of. That's the issue dealing with salt water, now imagine the condition of the exhaust cover and cylinder head bolts...

Happy Boating

 

[thewillhartleys]

Well apparently whomever put the lower unit on last, didn't use the spring washers so they're apparently seized from bottoming out rather than just corrosion. The top end is surprisingly very clean

 

[Captain Caveman]

That'll do it!

"Gee, why are there always extra parts laying around after I'm done working??"