Fuel tanks full or empty for layover?
 

I learned to always fill the gas tank and stabilize for the winter. Then the "experts" started saying that the additives in todays gasoline were actually attracting water so run the tanks dry for the winter. Now full tanks are being mentioned again. Opinions please.

Hey Bucky,, It's always been my thought, that if I fill it up, that leaves less room, in the Tank, for Moisture Build-up!!

I fill them up. Maybe not this year with the price of fuel. However the boat is staying inside in a heated space so I will not have the moisture problems.

Jon

Fill 'er up!

If its cool when you fill it, only to go 95% so the gas has room to expand. On a hot spring day it will puke out the vent if its 100% full.

Yeah, I found that out last spring:mad:

When I store my boats I always fill up 95% as Formula31 said...when I got the boat I have now it was near empty when the previous owner stored it, when I took it for its first maiden voyage it had water in the fuel....made it back to the dock at idle put dry gas and fresh seperator filters on and was ok......up to then any other boat I had never had a problem when it was stored with a full tank....Fred

One more vote for full, stabilized.

just keep using it all winter... no problem then:D

I run my tank dry-- The gas wont run in my engines by spring. I have an electric fuel pump that I hook up and pump the last of the gas into my wifes car all winter. (She doesn't drive much)
Since I started to do this I have not had any problems.

We don't have the long storage periods you guys do that are in the colder parts of the country, but when I was getting my pilots license I was taught to keep the tanks full so there was less room for water. I would think the same would apply to boats.

thanks everybody
 

Hell, after I filled it up today I just had to go for a ride. Only one other trailer in the lot at the ramp and he pulled in right after me. Damn water was 63 degrees, two weekends ago at Lake Gaston it was 80 degrees. What a difference. I thought me and my buddy Ed would put overboard at Cambridge and ride to the boat show, but winds were forecast at 15-25 knots, screw that. I'll just have to fill it back up again tomorrow and then it's time for it's winter sleep.

Stabilizer, fill it up and take it for one last short ride. That way there's room for expansion, but not much room for moisture.

What layover?:D
We don't need no stinking layover here in Fl.!

J/Kidding, fill her up to 95% and stabilize.
Good luck,
MD

OK guys, this is just my $.02 - so you can do whatever you want with it. But, I would feel bad if I didn't at least share this with you.

Seems as though it is unanimous, but I have to go against all those who say "fill it". Typically, that is what everybody does and you all survive the winter. But..............this is what the Mercruiser Tech's at Lake-X say. Their advise is to store it bone dry. YES......you will get condinsation in the tank. BUT, it is less harmfull than bad gas. They said the additives and the quality of the gas are so bad now a days, it won't last more than a couple months. They state the gas in the Southern regions is worse yet. Yes, it will start the boat and run. But what is the first thing people (that have to winterize) do on the first run of the year?? They go balls to the wall with it (after paying on it for the last 6 months). The octane level is so low, this is what will typically pop the engines. They say to fill up with good gas in the spring, then change the water separator after the first tank.

H2O separator : $6.95
New engine : $ ????

Makes sense to me.

Just passing along what I have been told.

CJC

What you said may be true if the pickup is totally at the bottom of the tank and you can get everydrop of water out in the spring. I know the few tanks I have seen the inside of are not like that. There is quite a bit of area in the tank below the low point of the pickup. It seems to me that every time you were running in rough water you would be getting water from the bottom of the tank. Ill stick with full and stabilized. Not to mention what water does to bare aluminum.

CJC,
I totally agree with this, especially if you don't have a metallic tank prone to corrosion.
I posted this exact question on another board, not knowing someone did here too. It seems that most people fill them up and put Sta-Bil or similar in their tank. I am emptying mine into the truck and leaving it dry.

The only other problem I could see was brought up by someone else. He had a fuel level sender rust from the condensation.

So add a $10-$20 fuel level sender and I would say that is a rare problem anyway.

I asked a Sunoco race fuel rep. the shelf life on race fuel and was told two months maximum if stored out of direct sunlight in a cool dry place. That would make you think pump crap gas has an even shorter shelf life.

In the summer months, I try to never let fuel get older than three weeks. I have heard from reputable engine builders that one month is all you have by the time it reaches the pumps.

Decisions,, decisions... ??????
 

My jet-ski needs to run on 92 ocatane (high compression) and I have debated whether to fill up or leave empty. I am hesitant to leave 15 gallons of fuel ( even with sta-bil ) in it for 5 months and risk loosing those precious octane points.

The last thing I need is sour fuel running through my ski at 7,000 rpm.. can you say kabooooom...

As for the Baja, leaving 80 gallons over 5 months doesn't make much sense to me either, I would rather run it down, drain it and leave it dry, then fill up with 80 fresh gallons in the spring..

Still un-sure..

Like I say - to each his own.

I would always top mine off before winterization and add the stabilizer. Never had any problems.

For the last two years, I have left only enough fuel to get me on the trailer. Didn't have any problems in the spring.

My friends got into this debate last year. Half filled them, the other half left them empty. We all made it out on the water. :rolleyes:

Just thinking about some of you big dawgs out there with some serious power. If you fill it in the fall, you might want to take it easy on the sticks until you get the good stuff flowing back through. :eek:

CJC

I would empty that jet-ski out. It has a plastic tank in it anyway. Hell, you could probably empty and pull the tank from the ski and keep it in your basement to prevent condensation.

I have always filled and sta-billed with my I/O's in the past. Now with the outboards, my buddy grenading both of his from gas left over the winter, (Sta-bilized), and talking to people in the petroleum industry, I am going empty for the winter.

Just to be clear...........

When I say "empty", You still need to add some stabilizer. Just thought that was a no-brainer.

Reason is...
 

You're filling the tank so there's less room for AIR,
which expands in the sun out the vent during the day.

Moisture laden air enters the tank at night
when things cool down.

Less air space = less moisture come spring.

Really, ya should fill up AFTER a hard days run, too.

Same reason.

Just to further confuse things... Here in Chicagoland gas is 10% ethanol. Mercury says to avoid it but if you can't never let it sit in the tank. So now what?

Fill it is what Merc says (but allow for expansion or it will overflow and leave stains on the boats around you or out of your vent)

This hits on some of the subjects.
I coppied this from this web site:
http://www.yachtsurvey.com/winter_lay_up.htm

There is plenty of controversy about whether gas fuel tanks should be empty or full at layup and you can find reasonable arguments for either condition. However, the argument for leaving them full overlooks the fact that modern gasolines go bad much too fast and six months is FAR too long. Old gas will definitely harm fuel injected MPI systems. Moreover, diesel oil is subject to bacterial blooms and oxidation as well.


Condensation developing in the tank is a much over-rated problem and here is the reason why: An empty tank contains a limited number of cubic feet of air, and therefore water vapor that could possibly condense. Air does not flow in and out through those tiny vents, plus you can always tape the vents over if that bothers you. The amount of water vapor in the tank comes to several ounces. However, if you have good Racor, Dahl or similar filters (which you should) these will easily be able to handle that amount of water. Smaller canister filters will be strained to get that much water out, but the large types like Fram cartridge filters can handle it.


What about fuel stabilizers, biocides etc.? While I'm not a petroleum chemist, I do know that these potions have a less than spectacular record of success. Personally, I'm not a believer in miracles sold in a can.


Therefore for both gas and diesel boats, it is best to arrange your fuel situation that the tanks be as empty as possible before you take the boat to the yard. Old fuel is a greater problem than a little water in the tanks.


Should tanks be completely drained for the winter? No, that isn't necessary. Besides, if you do, you'll have to refill them from 5 gallon cans in the spring which is messy, hard work and dangerous with gasoline. Leave just enough to get the engines started in spring and get to a fuel dock.


The old fuel left in the fuel lines is one of the reasons we have so much trouble getting engines started in the spring. In the spring you can bring a gallon of fresh fuel and prime the filters with it for easier starting.

*************

Sorry, they didnt even touch the issue of aluminum tank corrosion and Ive never had a problem with carburated motors after fuel sat for a lot longer than 6 months. The debate goes on.

MY engines won't even run with the bad gas. And they are only 600 HP 502's. The carbed engines will have the worst effects since an EFI engine will just detune for the bad gas. I pump it into my wife's suv and even it looses milage as the gas gets older.

While reading this topic this thought came to my mind. There are a lot of boat dealer businesses that are in the colder regions that would have to winterize their boats. I’m talking about the new ones that were taken out for demo rides and all the ones that have been taken in on trade. I can see them adding some stabil to the gas that is in the tanks but I would find it hard to believe that they are filling up all of the boat tanks during the winter months.
Just something to think about,
Cordell

What about keeping your tank full in the summer months when the moisture in the air is much higher than in the winter.

I try to keep my boat fairly full in the summer but probably like a lot of people I usually fill it before I go boating and then it seats all week with whatever was left in the tank. Since the air is holding much more moisture in the summer than in the winter this could be just as big as a problem.

Since I can never get a clear answer I just put stabilizer in with whatever I have left in the tank at the time I winterize. Also, be sure to run the engines to get the stabilizer in the fuel lines.

Someone mentioned what dealers do about boats on their lots and I'm sure their decision is based more on economics then what's good for the boat. I bought my boat in March which I know was on the dealers lot for over a year, I had a problem with water in the gas tank and had to run on one engine in August for 3 hours to get back to the ramp, and it was stinking hot.

Why did I have one engine? Formulas port side engines have the lower pick up in the gas tank and it was picking up a majority of the water, so it crapped out. So if you have a Formula you want to keep an eye on the port side fuel separtor to determine if you have a water problem. Although you should probably check both.

Oh yea, if you think it's expensive to put gas in your boat it's nothing compared to getting it pumped out.

CJC,
your just cheap
LOL
anything not to spend a buck.
funny how a credible argument can be made for either side.
I would rather leave 3/4 full and stabilize. Add some on the way to the first fire up. never had a problem, but then again...either way most have not had a problem according to this thread.

Can someone say when they had a problem????

I did 1995...454 carb. Left with about 3- 5 gallons in the tank for winter. Only time I ever had problems...last time I left her dry