View Full Version : Tank problems.

08-31-2010, 09:03 AM
I did not use my Donzi last year at all because I drove my Formula every time out. This year after looking what I spent on gas in the Formula I decided it was time to use the Donzi more again. Well all the sudden I am getting TONS of crap in my filter at the carb (I assume the canister filter as well) and it is impossible to keep the boat running at idle after I go out on the lake unless I mess around with the carbs idle mixture screws. Take out and clean the filter and it runs well again. Some one said that there was talk about something I can add to the gas to help clean out the tank? The stuff in the filter is not white like I have had in the past that I clean out once and I am good for the rest of the year. This stuff is brown. Looks like the Ethenol is cleaning off the old shalac in the tank? Any help would be great. I am going to try and put a new canister filter on this weekend and see if that helps. Any other ideas?


08-31-2010, 11:31 AM
Ethanol fuels ARE NOT YOUR FRIEND...try to find a source without it...

Definitely change your canister filter and get one to change that one too...

You might consider draining the fuel altogether and flushing it out...it does present some challenges

1. Getting Fuel out...can be accomplished with an older series F150 or Chevy fuel pump. You can get these at any auto parts store for $30-50...you'll want to lengthen the wiring and put alligator clips on as well as a longer intake and exhaust hoses. You'll need someplace to put the old fuel, contact you local fire department and offer to donate the fuel for their next training fire, sometimes this works but find a place to safely legally dispose of old fuel. I used 15 foot wire leads to get the battery away from the source of fumes, use an isolated battery, don't use the boat battery...removing this much fuel into containers generates a good bit of fumes...have a fire extinguisher handy...take all precautions for fire...

2. Tanks empty...now to clean... A few (3-4) gallons of kerosene are then sloshed around the tank with 25 or so miles of city stop and go style driving, pulsing the brakes, turns and such to clean out the residue in the tank...the tank is then emptied of its contents as in #1

3. Return the tank to service...NEW filters and NEW Fuel, replace all inline filters, canister, individual and wire screen on carbs...replace fuel and plan on running boat for several hours to use a goodly portion of this new fuel. I personally would run the boat thru its paces, jumping wakes and such to further scour the inside of the tank by sloshing the fuel around vigorously. Before I got home after this I would throw in an appropriate fuel stabilizer and fill it back up... along with replacing the fuel filters I replaced prior to the run...yes...changing a filter is cheap when considering engine damage or a tow bill.

Some have even mentioned using a gallon or two of acetone instead of Kerosene. I haven't tried this but it seems reasonable to have a solvent in there vs gas or kerosene to dissolve the solids, varnish, or shellac that might be built up inside from years of use...

The next best thing would be to pull the tank and replace if its suspect...very labor intensive and expensive but something to consider especially if a restoration is at hand or in the near future...

Capt Beach

08-31-2010, 11:41 AM
Here's another method to empty the tank;


08-31-2010, 11:23 PM
Thanks guys. I will see if I can kick this over the long weekend.

09-01-2010, 02:15 AM
I decided not to use my old tank anymore- just because I was curious I opended it up to have a look inside.
What I saw in there told me it was the right decision not to use it anymore: bizarre white slimy stuff you would never get out of it because of its consistence and the baffle plates and for sure it will contaminate your fuel..

...so everyone who says my old tank is still good I am sorry to say "replace it"!!