Should we replace our fuel in our new-to-us boat?

josrulz · #1 (**permalink**) 02-02-2009

Hi all,
I'm wondering if we should drain and replace the diesel fuel in our, which we just purchased. During the survey at the end of December, I noticed that the 20 gallon fuel tank on the boat was about 5/8 full. The boat is winterized and on the hard (in the northeast), but we ran it for the survey and re-winterized it. I would have prefered that the tank be nearly full for the winter, but we didn't own the boat then, so no choice.

The fuel tank is only about 3-4 years old, which is great, so it doesn't have 25 years worth of crud in it. The Racor fuel filter bowl looks very clean, and continued to look good while we ran the engine for about 30 minutes at survey. We'll also be doing a sea trial in the spring before we make the trip home to the Chesapeake. I'll also be replacing the fuel filter, and bringing several spares.

All that said, the fuel in the tank is probably at least a year old--the boat didn't see much use last year, and of course it's 5/8 full which means potential condensation and growth (at least theoretically).

So my question is, do we need to drain the tank and refill with fresh fuel before spring? Is there a big risk of water and/or growth in the tank now?

Please let me know what you think.
-J

gtod25 · #2 (**permalink**) 02-02-2009

While I don't believe that you will have any problem with the fuel and you could just add an additive, I could bore you with my story of having the engine shut down, in the middle of the Caribbean, shortly after I bought my boat. But suffice to ask what your wife will do to you if the engine splutters in the middle of your first long trip. A good cruising policy is "if you think it, do it".

SteveInMD · #3 (**permalink**) 02-02-2009

I would just add a biocide and a treatment like PRI-D. You can find these at most any marine store. Some people would say even that isn't necessary. Just top up with fresh fuel.

Before heading off on a long trip be sure to motor at cruising speed (80% of max rated rpm) for an hour to make sure everything is working correctly and the cooling system is up to par. On a long trip you may well end up motoring at cruising speed for a long time. It's not too uncommon for boats that never get run a full cruising speed to have a sticky thermostats or other cooling system issues. A sticking thermostat is not a big deal, but you'll want to know about it before you leave.

JohnRPollard · #4 (**permalink**) 02-02-2009

I guess opinions will vary, but I wouldn't be overly worried about it.

One option is to top off the tank using jerry cans this winter, being sure to ad a fuel stabilizer.

If you can't do that, I would top it off at least several days before departure and give it a good hard workout locally. Check the fuel filter/water separator after several hours of hard running and see if it tells you anything.

CalebD · #5 (**permalink**) 02-02-2009

I'm with gtod25.
This is like most boat maintenance items.
If you are feeling lucky then use the fuel that is in the tank.
If you want a clear conscience about it then drain the tank completely and start out with fresh fuel. You would hate yourself if your engine stopped while delivering your boat to the Chesapeake due to fuel and you HAD considered this as an option. If you do this then you should know that at least you started with clean fuel even if your engine dies for some other reason.

josrulz · #6 (**permalink**) 02-02-2009

Yeah, I suppose everyone will have a different opinion. Part of the problem with a long-distance purchase, is that it's really quite complicated to do any real projects while the boat is so far away. I mean, when I'm close to home, if I forget a needed tool, I can run home and get it. Up there, I have to run out an buy it, or wait until the next trip.

So I'm trying to limit the stuff I have to do before the boat comes home to only necessary stuff, and then pay the yard to do anything that I can't manage from afar (which I would prefer be a short list). Perhaps the fuel is one of those things I'll just have to pay the yard to do. I'll have to pay them to dispose of the fuel anyway... Hmmm....

xort · #7 (**permalink**) 02-02-2009

getting rid of the fuel is relatively easy. BUT, will that get rid of the possible problem? If you are really concerned with this then you need to have the tank CLEANED after you empty it.

Here is a way to test:
Pull the fuel guage or the fuel sending unit; whichever you have. This gives you a nice sized hole in the top of the tank. Take a clear plastic tube that is about a foot longer than the depth of the tank and put your finger over the top of the tube and dip the bottom of the tube down to the bottom of the tank. then pull your finger off the top to draw in some fuel from the bottom. Put your finger back over the top of the tube and pull it up out of the tank...how does the fuel look inside the tube? Clean? then you're set. A little bit of dirt & a little cloudy then pump out the fuel and replace. If it's real dirty & cloudy then you should consider a tank cleaning. Since the tank is not very old I doubt this will be needed.

Good luck

camaraderie · #8 (**permalink**) 02-02-2009

Jos...just get the fuel POLISHED if it is only a year or so old. Theat will get rid of most of the crud or water. Bring a half dozen racor filters with you on the trip anyway and make sure you know how to bleed the engine before the trip!
These guys may be able to help across the sound if you can't find someone local.
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blt2ski · #9 (**permalink**) 02-03-2009

Who is to say the fuel is only a few months old! personally, I would add some algaecide, maybe a water remover, and many filters, and head off! Then again, I have had very few fuel issues with diesels in the 20 someodd yrs I have owned them, now gassers.... yee haw, many issues with water!

marty

Omatako · #10 (**permalink**) 02-03-2009

It's a pity you don't live near me - I would buy the fuel from you for 10c a gallon.

No polishing, no risk, you make a quick buck - I could be your saviour.