Some very essential questions.
1. How old is the boat? If more that 10-15 years see #4
2. Was there diesel
in the tanks
for the 2 years it was sitting? If yes, see #4
3. Are the tanks aluminum
? If yes see #4
4. Clean the tank. At the absolute very minimum, very carefully inspect the tank.
I have a 30 year old Pearson
. When I bought it and sea trialed it ran fine. Owner always kept biocide in the tanks. First time I got in the ocean the filters clogged. I emptied tanks, flushed the tanks, swabbed them through the inspection
plate and still was clogging filters.
The only way to really clean the tanks is solvent or steam. If you can access them you can do it in the boat. Pain in the butt but can be done.
If the tanks are dirty polishing the fuel is like putting a band aid major wound. It might slow the blood flow but it isn't going to fix the underlying problem.
When I started cleaning
the old crude and crap out of the bilges I also found diesel leaks
. Pulled the tanks and both were full of black slime and were corroded on the bottom where the slime and water
collected while the boat sat at the dock
. Cut out a large part of the bottom and welded in new Al. Steamed the tanks while I had them cut open. Worth every minute for the peace of mind.
Check this old thread for pictures of the inside of an old tank.
The inside of a fuel tank