Cleaning a fuel tank

Mar 20, 2012
3,983
Cal 34-III, MacGregor 25 Salem, Oregon
DIY cleaning procedure for fuel tank follows, but when looking in the gauge sender hole of a steel tank, if its more than slightly rusted on the inside, the tank should be removed, and thoroughly inspected for imminent pinhole leaks on the bottom.... its common for tanks with lots of interior rust to start leaking after a cleaning...

but if it just has some slight surface patches of discoloration, this is normal....

aluminum is harder to tell.... but they usually corrode thru from the outside, rather than the inside like steel tanks.

for cleaning its best if you do this when you only have about a quarter tank of fuel.
get a high volume fuel electric automotive pump and set the intake line (3/8") up with an in-line plastic "see thru" filter.... and pump the fuel out thru the sender hole into a container(s) large enough to hold it all, running the suction line all over the tank bottom, or, if the tank is contoured to the hull, its easy to suck along the lowest edge/corner of the tank.... in pumping this way, you are vacuuming the tank bottom.
you should have a couple extra filters in case you have a lot of debris and it plugs the filter.

then once you have removed all the fuel, reverse the pump and put some back in, trying to pump the fuel up on the sides of the inside of the tank to rinse any particles down to the low point.... than after a gallons worth of rinsing, suck it out again......

at this point, I recommend changing the filter... and then pump all the fuel back in, but DO NOT suck from the bottom of the container, as its possible that there may be some water at the bottom .... keep the suction line off the bottom at least 3 inches until you can see what you are sucking up.... you should be able to put nearly all of it back in the tank... and discard the any water contaminated fuel and the debris laden filters.

with a couple towels and a bit of care this should be a clean job and take about 30 minutes...
 
Apr 7, 2014
8
Hunter 30 Nyack, NY
IMG_2650.JPG
Ahoy,

I am re-powering my 1979 H30 and it is a perfect time to clean out my fuel tank. I have been looking for input on the best way to do this. The most common advice I have gotten so far is to take it out, put kerosene in it and shake it up. Anyone have any other ideas on how to clean out these original 12 gallon tanks? It is in perfect condition and I plan to keep it.

Thanks,
Bob
I did the entire area of the fuel tank in 2015. I have an 82 so the fuel gauge always leaked and saturated the plywood holding the tank. The Ply delaminated. I had to toss the water heater and pulled the tank to thru the starboard Laz. Epoxy coated the new ply and used a wire and turnbuckle arrangement to strap down tank. The wire does not touch the alum tank. I put the new type fuel level sending unit. Works great. No leaks. Also pressure tested the tank at 3psi. Some exterior pitting on bottom of tank. I coated bottom exterior with JB Weld. No Leaks. Smell of Diesel is gone.
 
May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
Just to be clear : You were able to remove the fuel tank through the starboard lazarette with no mods to the area?
This is a question many H30C owners have asked but no one admitted to actually doing it!
Thanks for the info in advance.
G.
 
Oct 6, 2007
1,023
Hunter H30 1982 Chicago IL
Ggrizzard,
On the '82 that would be so. No problem. The water heater in front of the fuel tank is another story. I would not assume that you can get the fuel tank out through the starboard lazzarette on all the Cherubini H30s. Hunter changed things from one model year to another.
 
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May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
Looking at your pic, the engine bay space to lazzerette is identical. I already removed the original water heater through the engine bay with a small mod to the lazzarette shelf, so I should be able to get the tank out through it if it will fit through the seat opening. As Hamlet said: "That is the question"
 
Jul 13, 2016
5
Hunter 30 Islamorada, FL
Yes, I removed my fuel tank through the starboard lazarette after I removed the inoperative water heater. Cleaning the tank now before replacement.
 
Oct 1, 2015
63
Clark San Juan 30 Blaine WA
Use use a shop wet dry vac to do mine as long as there is hardly any fuel it it works pretty good I have a 3 inch inspection hole with a cap I just unscrew it and use the vac with a flexible hose and vacuum away does a pretty good job then I add a smudge of water and just vacuum it AGIAN try it it might just work well for you it looks like quite a job to pull it out
 
May 27, 2004
1,964
Hunter 30_74-83 Ponce Inlet FL
Mbirk, thanks for the info and confirmation. I will measure twice so that I don't have to cut once before I remove the tank.
Really wasn't looking forward to the alternative. :yikes: