1. Take all the foam cushions off the boat, and open some ports
and a hatch
2. Make sure there are no fuel leaks
anywhere, between the tank (which could leak, itself) and the injectors.
3. Make sure the engine is totally clean, too; use degreaser and rinse. Dry it with rags to get any remaining grease off.
4. Clean the bilges, to dinner plate cleanness. (May take hot water
and t.s.p., and then rinse.)
5. Any timber that has black, oily stain, use degreaser and rinse thoroughly. Dry with clean rags or paper towels.
6. Leave the cushions and the boat airing, and go visiting or for a cup of coffee.
7. On your return, below decks should smell fine, if you found all the leaks
. If not, you missed something, and need to repeat step 2 and possibly 3, and probably not 4 & 5 if you did a good job.
8. The rest you do at home. Next, try smelling your cushions. If you can still smell diesel, the covers may be savable, by careful, thorough washing
, but don't use real hot water
, due to the possibility of shrinkage, if they're soft fabric
not plastic. You can try washing
the foam in the bathtub, with dishwashing detergent. You'll be surprised how dirty they are. Rinse till the water is clear and non-oily. Then you have to air dry them, vertically arranged, if possible, so the water drains out, and this will take a while...like a couple or 3 days of good drying weather
. After the cushions are dry, smell them. If they're okay, you've just saved a bunch of money
. The cushion covers, smell them, too. If they're okay, too, you just hit a home run! If not, it'll be time for new foam and possibly new covers, as well.
Good luck with it.