Repower or backup????

I have an '86 Step V with a '97 Johnson V6 225 and keep it on Lake Michigan. I have had several tows this year because of outboard breakdowns. I have replaced the fuel pump, starter. It seems to have more white smoke than other motors its age.

I want to do longer distance trips next year but question the reliability of the outboard in open water.

I am considering putting a backup outboard for greater piece of mind, or spending some dollars and getting a recent used Yamaha 175 or 200HP.

What do you guys think?