Re: new style t-sats on a 1986 140 looper
The 1995 parts will work. Just go the the Evinrude site and look up that motor. You'll need the cap and spring (use as a set) and a gasket. If you have the black t-stat assy just unscrew the rubber gasket and you're good to go.
If you still have the old white assy (doubt it) then order the new assy too. You'll have to cap off the small water line from the adaptor plate to the control valve, which you'll discard.