Do you fill the tanks for the winter?

Peterb21

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Hi, I have a 2003 Sailfish 282 with twin 4 stroke 225 Yamahas each at 1150 hours2. I have 2 gas tanks. The Main is 150 gallons and the auxillary is 50 gallons. The auxillary is full and the main is only about 1/4 full. I typically fill the tanks and add Yamaha fuel stabilizer over the winter months. The boat is out of the water from November to March as I in the Northeast.

So everyone I talk to and what I see online says to fill the tanks and add stabilizer. My mechanic just winterized the engines and he is telling me NOT to fill the main tank. He says that he would rather have a fresh tank of gas to start off the season rather than a full tank with stabilizer.

I'd love to hear anyone's thoughts on this one?

Thanks!
 

Hookup1

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DennisG01

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Generally speaking (especially with aluminum tanks), you either want them full or empty - nowhere in between. Since emptying a tank isn't always the most convenient thing to do, that leaves filling them as the option.

With stabilizer added, the gas will be TOTALLY fine. Heck, it will be just fine for an even longer time. FYI, use stabilizer year round - it's good for your engine/injectors, too.

You'er going to run the stablized gas through the engine, right? It's important that the injectors have stabilized gas in them to avoid them gumming up.

The reason behind this "empty or full" thing is not about the quality of the gas (as I mentioned above), it's about water getting into the gas from condensation. A tank that is partially filled will experience condensation. An empty tank will not and a full tank will experience near zero condensation.

Although not very convenient, it's not all that "hard", either to pump out the gas - you can do it through the fuel sender pretty easily. There might be crap in the bottom of the tank, anyways, and it would be good to get it out of there. Let the gas settle in whatever you pump it into and then you can pump the "good portion", a few gallons at a time, into your cars.

Now... how much condensation could happen? There's no one best answer. There's too many variables - daytime/nightime temps swings, sun/no sun, atmospheric moisture, etc. You might get very little (or near none) or you could get enough that you need to pump it out.... but you will likely only notice this AFTER you fill up the tank in the Spring... and now you're dealing with 150 gallons. Although you would only be pumping out till you got to clear gas, of course.

The better quality stabilizer you use, lessens the chance of condensation causing an issue - depending on how much gets in there, of course.
 

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Thank you. Great information here.
 

Peterb21

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Generally speaking (especially with aluminum tanks), you either want them full or empty - nowhere in between. Since emptying a tank isn't always the most convenient thing to do, that leaves filling them as the option.

With stabilizer added, the gas will be TOTALLY fine. Heck, it will be just fine for an even longer time. FYI, use stabilizer year round - it's good for your engine/injectors, too.

You'er going to run the stablized gas through the engine, right? It's important that the injectors have stabilized gas in them to avoid them gumming up.

The reason behind this "empty or full" thing is not about the quality of the gas (as I mentioned above), it's about water getting into the gas from condensation. A tank that is partially filled will experience condensation. An empty tank will not and a full tank will experience near zero condensation.

Although not very convenient, it's not all that "hard", either to pump out the gas - you can do it through the fuel sender pretty easily. There might be crap in the bottom of the tank, anyways, and it would be good to get it out of there. Let the gas settle in whatever you pump it into and then you can pump the "good portion", a few gallons at a time, into your cars.

Now... how much condensation could happen? There's no one best answer. There's too many variables - daytime/nightime temps swings, sun/no sun, atmospheric moisture, etc. You might get very little (or near none) or you could get enough that you need to pump it out.... but you will likely only notice this AFTER you fill up the tank in the Spring... and now you're dealing with 150 gallons. Although you would only be pumping out till you got to clear gas, of course.

The better quality stabilizer you use, lessens the chance of condensation causing an issue - depending on how much gets in there, of course.
Thanks. I appreciate the info!
 

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There seem to be more variables than you would normally think. I have never filled my tanks for winter storage and have left whatever gas was in the tanks after the boating season and that is usually 1/4 tank or so. I never had had a water issue in the spring. ( I do add stabilizer and run the boat at sea to get things mixed up in the tank) When relatively easy to do, I drain gas from the engine mounted fuel filter and VT tank. ( One model motor is easy, the other is a royal pain).
I can't explain why many boaters say that a partial tank is problematic. It hasn't been for me. If my gas were to go bad or get contaminated with water, I would much rather have 30 gallons of gas to get out and get rid of than 130 gallons.
My boats are stored in the NY metro area and the Jersey shore area. One has an aluminum tank and one has a poly tank. Both hulls have vented combo fuel fills. Boats are covered with canvas covers and get pretty hot under the cover in the sun but are not air tight.
Maybe I have been lucky but I have 17 seasons on one boat and 6 on the other.
 

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Near as I can tell my water in fuel problems were related to o-rings missing on fuel fills.

My tanks are never full and typically close to empty. I pump out my no-ethanol FL gasoline and use it with my lawn equipment.

I had a strange incident one year in NJ when I added stabilizer in preparation for going to FL in a few months. I took the boat out of the slip and started to run it to stir things up and get the stabilized fuel un into the engines. Didn't get far before the boar started running badly. Go back to marina an had water in filters. I would have bet the fuel stabilizer had something to do with it but have no way of proving it.
 

seasick

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Near as I can tell my water in fuel problems were related to o-rings missing on fuel fills.

My tanks are never full and typically close to empty. I pump out my no-ethanol FL gasoline and use it with my lawn equipment.

I had a strange incident one year in NJ when I added stabilizer in preparation for going to FL in a few months. I took the boat out of the slip and started to run it to stir things up and get the stabilized fuel un into the engines. Didn't get far before the boar started running badly. Go back to marina an had water in filters. I would have bet the fuel stabilizer had something to do with it but have no way of proving it.
I have seen similar events in other members' boats. I know for certain that too much stabilizer can cause issues but that event seems to be more common with specific brands.
I have also seen the water problem in tanks that were treated for storage. I wonder if there may have already been water mixed in the existing fuel that somehow precipitates out when some additive are used.
Regarding the o-ring statement. I would bet that nine out of ten complaints about water and lots of water in the tank turned out to be intrusion due to bad o-rings.
 
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Hookup1

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I have seen similar events in other members' boats. I know for certain that too much stabilizer can cause issues but that event seems to be more common with specific brands.
I have also seen the water problem in tanks that were treated for storage. I wonder if there may have already been water mixed in the existing fuel that somehow precipitates out when some additive are used.
Regarding the o-ring statement. I would bet that nine out of ten complaints about water and lots of water in the tank turned out to be intrusion due to bad o-rings.
The boat was in the water and being used a few weeks before this happened. I feel that adding the stabilizer caused the water and alcohol to drop out. I can't prove that.

After a few years of fighting water in fuel problems it was either you or SKUNKBOAT that go me to finally look at the o-rings. Completely gone both fills. Since then it hasn't been a problem.
 

DennisG01

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The boat was in the water and being used a few weeks before this happened. I feel that adding the stabilizer caused the water and alcohol to drop out. I can't prove that.
Water will bind with the alchol and cause the combo to drop to the bottom of the tank. But stabilizer (Startron, for example) will not cause that. Startron will, however, bind with the water and pull it out of the fuel and, to an extent, disentegrate it enough to where it will pass through the engine without harming anything.

In other words, the stabilizer will NOT bind with the ethanol, however WATER will bind with the ethanol. This is called phase separation. The Startron can only do so much, though - it can take care of a small amount of water and help ward off problems - but at some point, with enough water in there, you'll still have issues.

In "other" other words... the stabilizer would not have caused your problem - it was probably just the timing of when you last used the boat vs enough water starting to accumulate in the tank by leaking in.
 
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Mustang65fbk

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I took my boat into the local GW dealer last winter to have it winterized, of which I only had about a half tank of fuel and then they added the proper ratio of Yamaha fuel stabilizer into the tank. I didn't have any issues with it this summer after have it winterized like that, and then I added only ethanol free gasoline when running the boat as there is a local gas station that offers it for not much more money than regular. I've heard of guys doing anything and everything in that some drain the fuel tanks, some do about half and others fill them up completely. If you do run regular fuel that isn't ethanol free and are going to have it sitting for months and months, I'd definitely run a fuel stabilizer.
 

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Water will bind with the alchol and cause the combo to drop to the bottom of the tank. But stabilizer (Startron, for example) will not cause that. Startron will, however, bind with the water and pull it out of the fuel and, to an extent, disentegrate it enough to wear it will pass the through the engine without harming anything.

In other words, the stabilizer will NOT bind with the ethanol, however WATER will bind with the ethanol. This is called phase separation. The Startron can only do so much, though - it can take care of a small amount of water and help ward off problems - but at some point, with enough water in there, you'll still have issues.

In "other" other words... the stabilizer would not have caused your problem - it was probably just the timing of when you last used the boat vs enough water starting to accumulate in the tank by leaking in.
It was Startron that I added. Most likely ethanol had adsorbed water but not to the point of separation. The Startron pushed it over the top and it separated out.
 

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Hi, I have a 2003 Sailfish 282 with twin 4 stroke 225 Yamahas each at 1150 hours2. I have 2 gas tanks. The Main is 150 gallons and the auxillary is 50 gallons. The auxillary is full and the main is only about 1/4 full. I typically fill the tanks and add Yamaha fuel stabilizer over the winter months. The boat is out of the water from November to March as I in the Northeast.

So everyone I talk to and what I see online says to fill the tanks and add stabilizer. My mechanic just winterized the engines and he is telling me NOT to fill the main tank. He says that he would rather have a fresh tank of gas to start off the season rather than a full tank with stabilizer.

I'd love to hear anyone's thoughts on this one?

Thanks!
I was always told empty tanks allows moisture, I always fill my tank before winter storage
 

Legend

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Hi, I have a 2003 Sailfish 282 with twin 4 stroke 225 Yamahas each at 1150 hours2. I have 2 gas tanks. The Main is 150 gallons and the auxillary is 50 gallons. The auxillary is full and the main is only about 1/4 full. I typically fill the tanks and add Yamaha fuel stabilizer over the winter months. The boat is out of the water from November to March as I in the Northeast.

So everyone I talk to and what I see online says to fill the tanks and add stabilizer. My mechanic just winterized the engines and he is telling me NOT to fill the main tank. He says that he would rather have a fresh tank of gas to start off the season rather than a full tank with stabilizer.

I'd love to hear anyone's thoughts on this one?

Thanks!
I Have always filled mine - I had heard it keeps moisture / condensation out of the tank. I know many that winterize with low levels of fuel and none of us have had any fuel issues. Most years the price of gas is higher than the last and it save me a few bucks and I do't get socked with a huge gas bill on the first day.
FYI you actually have more capacity than you think if your tanks are factory installed. The 03 Sailfish came equipped with a150 galllon main tank and the auxiliary has 70 gallons for a total of 220 gallons.
 

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This thread pops up on every single boat forum in the fall every single year. There is no "right" answer. Do what works for you.
Previously I always filled it (and stabilizer at every fill); this year it has about 1/3 tank. I want to be able to start in the spring with "fresh" fuel as I didn't use a lot this year (never had to refill).
 

DennisG01

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I was always told empty tanks allows moisture, I always fill my tank before winter storage
As I noted above, condensation can happen when there is a difference in temperature between the holding vessel (the tank) and the liquid inside along with moisture suspended in the air that enters the tank. In this case, the fuel remains at a certain temperature while the aluminum (where it's NOT in contact with the fuel) changes temperature quite rapidly. The colder the climate, the less of an issue there will be. Empty tanks don't experience this problem because there's no liquid.
 
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I fill mine for the winter lay up.
 

Fishtales

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Never have filled. Just do my best to run down but to be honest some years around 1/2 in the tanks. Treat the fuel and fill in the spring. Never an issue in 25+ years. I've heard the same thing from guys that fill as well.