Fuel Tank storage - Empty, 1/2 Full or Full

S

Searaybio270

Active Member
Jul 8, 2010
1,058
Bush River on the Cheasapeake Bay
Boat Info
1996 EC, Garmin 3210, Dinghy - Seadoo Jet boat with twin 85 horse. Fun and Fast.
Engines
7.4 MC 360 HP each
Westerbeke 7KW
First - I did try searching within the site for question above but one I couldn't find anything and I am running out of time.

So, I am getting ready to Haul out. In years past I have always filled my tanks and treated them with some form of fuel stablizer. I have done a ton of research on fuel and the theories on the Title of this thread for our marina and for my own info.

However, today I am not sure what to do. So any input/ideas would be greatful.

Thanks,
Joe
 
I don't worry about filling the tank as long as it's at least half....aren't these tanks usually aluminum anyway? I use fuel stabilizer and never worry........the fuel I get doesn't have ethanol.

Has worked for me.
 
Actually, leaving the tank less than full is more of an issue with aluminum than it is plastic. Aluminum will condensate more than plastic. The two 'best' options are either completely empty (not very practical for anything more than 6-gallon portable tanks) or full and stabilized. Use ethanol stabilizer if needed. Will a half-empty tank absolutely lead to problems? Maybe, maybe not - but it's a variable that can easily be avoided.
 
I leave mine pretty low. I don't like the extra 1,900 pounds sitting on keel/jack stands. I have never had an issue. Our fuel is 89 octane without ethanol. I stabilize and top it off in the spring.
 
Our fuel has ethanol in it. I too don't like to have a full 300 gallons on board as it sits there for 5 to 6 months. Everything I read says the same things you guys are saying. Just not sure what to do, just Yet that is.
Thanks so far -
 
I treat mine with Sta-bil and leave whatever is in it... It's been anywhere from a quarter to half over the years and I have yet to have a problem. I change the water separator filters every year. I use 89 no ethanol.
 
3/4 to Full. Ethanol Free. If the tanks are over three quarters, I don't bother topping it off at the end of the season.

Never added stabilizer, never had a problem. Been doing this for 40+ years counting my boat and my Dad's boat.
 
I have always done full and used starton fuel treatment at the initial dose mixture vs maintenance dosage. So far so good. Also I change my water separating filter every year, and have minimal if any water in the fuel when I dump the filters out into a glass jar and let it settle. I do run startron in the maintenance dose at every fillup though.
 
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Since the inception of E10, I decided to store FULL and keep the tanks Startron'd with the appropriate dosage at all times (even during the boating season).

Didn't work out so well for me when my previous boat sunk with $1000.00 worth of gasoline aboard. Allstate told me that is not a covered expense.

Other than that I have never had any fuel related issues in the 10 or so years since the ruse that is E10 started.

Food for thought...store empty and top off in the spring...how long has the fuel been sitting in the tanks at the fuel dock?
 
I store mine full. Non ethanol gas. I add 1 gallon of SeaFoam when I top off for the winter. Then it sits 8.5-9 months, so far I've never had any problems.
 
In my mind, there is no question, considering all the factors involved - tanks full, Sta-bil mixed in per manufacturer's directions. This methodology is most resistant to condensation forming in the tanks, period. If your boat is properly blocked, the fuel in the tanks won't cause an issue due to weight.

Dale
 
Just returned from one of the Marine stores here on Lake Erie. The owners commented that the current trend up here is to leave the tank as empty as possible with some stabil. He stated the low temperatures up here are unlikely to create much condensation. He then said storing full is also OK, but his point was that those who store empty up here need not worry about any moisture in the tank if stabilized.
 
This is one of those "what kind of oil is best" questions....there's going to be loads of real life experiences...none of which will agree with each other.....good luck in your choice.
 
Empty or full, the main thing either way is to use fresh non ethanol gas, if possible, and treat it before you run it the last time. Make sure treated gas is burning before you shut down the last time. If you go full, don't go too full. Temp changes can force fuel out the vent if the fuel expands and there's not enough room for it.
 
I get my final pump out this Monday and will put a few hundred in each tank. Yes it will have ethonal but the marina stabilizes my boat and I have never had a problem with fuel in the spring
The summer I had my heart attacks saw us not use the boat till the following summer. Two years that fuel sat in the tank and the boat started and ran just fine. You think the marines stabilize the fuel that sits in their storage tanks all winter. I look at it this way, one less expense come spring. Besides the price of fuel is alway going up right now we are paying 1.60 a liter, thats 6.05 a gallon.

Ken
 
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Thanks Everyone for your input. I agree that it can be either full/empty. I will probably go with almost full again this year. I still have my 270 Sundancer. The fuel in there has been treated and it has been sitting for almost 4 years. This summer I started both engines and the boat started and ran without issue. Yeah, I was shocked, too.
I hate hauling out.
 
I filled mine last year as fuel prices are lower where I am during the fall...so there is a financial reason, plus one less thing to do at launch time.

As far as full or empty, I just always run Stabil and never have issues.
 
Depends also on how secure your boat is. Boats that sit with full fuel tanks on stands can be siphoned of fuel if not in a secure area. I always put away full. I fill the tanks with stabilizer and run around for a bit to allow for some expansion and mixing of the stabilizer.
 
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