engine mercruiser 488 year1983

Question
HI. Motor is bolted on the back to the transom plate with 2 long bolts that i cannot take off (rust and salt water)
I tried all sorts of loose nut liquids with no success.I tried with a big impact wrench,no succes.And it takes a miracle to reach behind the motor,no room to work.I am discourage. Please HELP     Thank you in advance R閍l

Answer
Hi Real...Thank you for selecting the undersigned to reply to your question.

By the way, I'm neither a mechanic nor a builder of boats but, not knowing the construction of your vessel makes it difficult to offer appropriate suggestions.

Is heating the nut out of the question, so long as the surrounding area is properly protected to prevent any consequential damage, or is it too difficult to reach with a torch?

Although an impact wrench with a socket wasn't successful in loosening the nut, have you considered trying a nut splitter attachment (with an extension if necessary)?

Failing all else, consult a qualified and reliable marine mechanic.

Safe Boating
Ron