How to clean the diesel tank 1986 Sabre 32

Jul 9, 2019
5
Sabre 32 Annapolis
Bought her in October. I recently couldn’t start the engine (it’s the original) and noticed the fuel filter was dirty. Had recently changed it (in Oct). Put in new filter and engine started up fine and took us 4 hours home. It had been a very wavy day on the Bay.
Thinking the wave action stirred up gunk from the bottom of the tank, I asked the service shop to polish the fuel. The company who specializes in this came out but said they couldn’t access the tank.
Anyone have experience with accessing the diesel tank to clean it out?
 

RitSim

.
Jan 29, 2018
406
Beneteau 411 Branford
I used a 4" hole saw and cut a hole in the top of mine. Make sure you have a pilot drill in the hole saw to hold the saw in position. If you GENTLY and SLIGHTLY tip the saw, the hand drill will handle the cut easier. Tipping the saw will make a slightly larger hole. Tip in various directions and securely hold the drill motor. Bought an aluminum 1/8" or 3/16" thick x 5" diam disc off of Ebay. Drilled 24 tap drill holes around the edge. Used the disc as a template to drill the tap drill holes in the tank. Then opened the disc holes to clearance holes for the #8 or #10 screws. Bought diesel resistant gasket material at the auto store. Clean the edges of the hole with a file. This gives you good access to the tank interior. I had a layer of scum on all the tank walls that took a little experimentation with various solvents - I think Carb cleaner was the final but can't be sure. Tighten the cover gradually with several passes so as to not strip the tapped holes in the tank. Some also advise checking the dip tube to make sure the tip is free of debris and remove any screen that may be there. Make sure the top of the dip tube is tightly secured to the fitting so no air is sucked in and to assure that you don't lose the tube in the tank.
 
Oct 22, 2014
20,993
CAL 35 Cruiser #21 moored EVERETT WA
Welcome @Blue Wolf to the forum.
Not having a Sabre, but having purchased a boat with two 89 gallon tanks partially filled and fuel old of unknown years. What would help is some images of your tanks. How big? Where positioned? what type fo access to the tank? What type of material they are made of?

I got an offer from a polishing company of $2500 per tank, to install access holes into the tanks, and polishing the fuel and cleaning the tanks.
I chose an alternative plan. I started using the fuel and swapping out the filters frequently. I polished fuel by pumping it from one tank to the other through a filter. I added fuel algae fighting substances to the tanks to kill and help to dissolve the gunk in the fuel. Took about a year. Now I have clean tanks and no more frightening stoppages to change the filters.

The process helped me get pretty good at changing filters. Best time 7 minutes in the middle of a Strait. It was calm, but I needed to do it to get out of the ship traffic channel.
 
Jul 1, 1998
3,062
Hunter Legend 35 Poulsbo/Semiahmoo WA
SeaBuilt Fuel Tank Clean-out Port, Tank Access Plate System, 6” (they make a smaller one, I think): List $171.00 when I got it, don’t know what it is today. Made (in USA at the time I got it) with stainless steel and a neoprene-type gasket. Really well made.

One you get started cutting there is no backing out, you have to finish including cleaning out all the cutting savings. Good time to check out the fuel gauge too.
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Jul 9, 2019
5
Sabre 32 Annapolis
Ritsim,
Thanks for all that good info! My main problem is that there is very limited access to the tank. It's probably never been cleaned. I just learned that the mechanic used a fiber optic scope a few years ago and found it to be clean. I'm having him do it again soon.
 
Jul 9, 2019
5
Sabre 32 Annapolis
Thanks, Jssailem. Because of the difficulty of accessing the tank, and the fact that the fuel filter is automatic bleeding, I expect I'll be doing a lot of fuel filter replacing until the tank is clean.