Question about built in gas tanks

Hey guys, I could sure use your advice. The Bible says there is safety in a multitude of counsel. So, please give me some counsel.

I have never owned a boat before that had a built in gas tank, but my new Crestliner has a 21 gallon tank. The owner's manual says to fill the tank each time you use it. Supposedly, according to the owner's manual, a full tank cuts down on condensation and thereby cuts down on moisture in the tank, which is one of the things that causes the "new" gas break down.

I would think that by leaving most of the gas in the tank and adding just a few gallons each time, the gas would begin to get old and then start break down which would cause problems anyway. My thinking says run most of the gas out and fill up with fresh gas, but this, according to the manufacturer, would allow condensation to start forming.

What are ya'll thoughts on this? What do ya'll normally do? Fill up each time or run most of it out and then fill up? Any advice will be appreciated. Thanks!

Stabil!

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Originally Posted by trobin

Stabil!

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Yep, I already use Stabil along with another fuel additive that my brother suggested.

A can of seafoam at the beginning and end of the season is what I use.... But my boat has always been run atleast twice a month durning the winter months

Pastor, I don't really believe you will ever have a condensation problem in this part of the country. A lot of it has to do with extreme temp differentials and long term storage. I would suggest if you are going to store for a couple of months or more that you fill tank and treat with Stabil. I run mine down then fill. I have run boats all my adult life in all kinds of climates and never had a condensation problem. If you are worried go to walmart and get one of those screw on water filters with the base and install it in your fuel line close to the motor as you can. Then change that filter once a year. Your biggest problem is age of gas when it comes to ethanol gas. It breaks down and causes what is called phase separation. That's when the moisture shows up. Believe it or not your gas has a certain amount of moisture in it all the time. It's just mixed really well and will not hurt anything until it starts to seperate. All that said to say this, run it down as far as your comfortable with then add make up gas.

I run mine so much I don't have to worry about it.....I do use an additive to clean the engine....never use with stabil......if I were going to store it for a long time, I would....

another important thing to do is charge your trolling batteries immediately after getting home....took me a long time to learn this....

Ethanol ( alcohol) is hygroscopic meaning it attracts water.............. This is much more of a problem than the unlikely event of condensation....Ethanol blended fuels will start to breakdown in 90 day's under optimum conditions and can start in as little as 30 day's............

In my opinion If a person plans to winterize their boat for several months I would recommend running out the ethanol fuel and filling with ethanol free fuel.........

With today's fuels every boat can benefit from a water separator filter installed ( just cheap insurance )

With high humidity and high dew points, condensation does occur. I have seen it a few times under the lids of my dry storage. I cannot keep my inflatable vests in the dry storage boxes during these times otherwise they will inflate. I don't have a problem with the fuel though. Like Cray said, all hydrocarbons (gas and oils) have some water from .03 to 2 % by weight which remains miscible and won't separate. To me, non ethanol fuel is a must. The boat manufacturers do recommend that practice just as an added precaution, but I don't think it will be a problem as long as a high quality fuel is used.

I keep my tank full and use an additive and ethanol free gas only. No prob gor 2 years and if anyone will have a problem it will b me. :)

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Originally Posted by fishervet

I keep my tank full and use an additive and ethanol free gas only. No prob gor 2 years and if anyone will have a problem it will b me. :)

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:hesaid

#1 is to use only non-ethanol gas if possible. #2 is invest in a good water separating filter & keep it serviced. #3 is use of a good fuel additive. I've been using Startron Enzyme ever since it came on the market. It is affordable and you can't easily "overdose" your fuel. It also keeps valves functioning correctly by cleaning varnish & carbon. I have a 11 gallon built-in tank in my crappie boat and just keep adding gas to my tank when it gets below half full.

Thanks for all of the advice everyone. CDC members are just the best of folks.

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Originally Posted by Pastor

Thanks for all of the advice everyone. CDC members are just the best of folks.

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And we think we know alot.

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Originally Posted by fishervet

And we think we know alot.

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and we can identify any fish......

LOL.

I have a 20 gal built in aluminum tank in my boat. I use Mercury oil , premium plus, (the plus means it has a stabil like additive already in it) and I run a water separating fuel filter. I change it every 2-3 years, actually just changed it a few weeks ago and drained it into a glass. I was expecting to see some water but nope, not a drop. That is good news because the gas I use contains ethanol and so far water accumulation has not been a problem. Also, I rarely top off my tank…so there you go. I hope you have as much good luck with your new boat as I have had with mine. By the way, mine was built in 1984, almost broken in…BC