I did something bad

[SpringFever552]

Fill it up, and take someone fishing/prawning

 

[Foxsea]

I would add some Methyl Hydrate or gas line antifreeze, to help remove any condensation. Run a tank or two, then change your water/fuel separator. I always carry a spare filter too.

Say no to ethanol. That's why we use mid-grade gas.

 

[Foxsea]

I wouldn’t say it’s a myth but it’s not as big an issue as many make it out to be I have had water in fuel issues occasionally over the years but its just a nuisance more so than a serious issue and doesn’t amount to much especially in a smaller tank. Separator and filter are in place for that sort of thing.. no big deal. Had an optimax that would trigger a water in fuel alarm almost yearly after sitting for the winter. Drain water change filter and problem solved.

David Pascoe (love him or hate him) covered this years ago. The science:

• There isn't enough air volume even within a large gas tank to hold much water vapor.
• On average, tanks are about half full, further reducing volume
• The amount of water vapor in the air is very small, even at 100% humidity
• Normal conditions aren't right to cause condensation in a fuel tank

Research produced the following values for the maximum amount of liquid water, in nomal air, at the following temperatures:

30C/86F	30 grams/cubic meter
20C/68F	17 grams/cubic meter
10C/50F	9 grams/cubic meter

There are 28 grams per ounce, so 30 grams = 1.07 oz; 17 grams = 0.6428 oz.

A cubic meter equals 264 gallons of liquid volume, therefore:

• A 200 gallon tank = 0.76 cubic meter.
• At 30 C, an empty 200 gallon tank could contain 22.8 grams of water vapor, or 0.81 oz.
• At 10 C, an empty 200 gallon tank could contain 12.92 grams of water vapor, or 0.46 oz.

Note that these are the maximum amounts of water vapor that a completely empty, 200 gallon tank could contain. In the winter, 10 C case, not even a half-ounce of water. Also note that in order to condense water out of normal air, a surface must be much colder than the air. But it's not normal air in the gas tank, it's gasoline vapor.

The problem for the winter condensation in a boat tank theory is "How can this happen?" It simply doesn't.

 

[Brando]

David Pascoe (love him or hate him) covered this years ago. The science:

• There isn't enough air volume even within a large gas tank to hold much water vapor.
• On average, tanks are about half full, further reducing volume
• The amount of water vapor in the air is very small, even at 100% humidity
• Normal conditions aren't right to cause condensation in a fuel tank

Research produced the following values for the maximum amount of liquid water, in nomal air, at the following temperatures:

​

30C/86F	30 grams/cubic meter
20C/68F	17 grams/cubic meter
10C/50F	9 grams/cubic meter

There are 28 grams per ounce, so 30 grams = 1.07 oz; 17 grams = 0.6428 oz.

A cubic meter equals 264 gallons of liquid volume, therefore:

• A 200 gallon tank = 0.76 cubic meter.
• At 30 C, an empty 200 gallon tank could contain 22.8 grams of water vapor, or 0.81 oz.
• At 10 C, an empty 200 gallon tank could contain 12.92 grams of water vapor, or 0.46 oz.

Note that these are the maximum amounts of water vapor that a completely empty, 200 gallon tank could contain. In the winter, 10 C case, not even a half-ounce of water. Also note that in order to condense water out of normal air, a surface must be much colder than the air. But it's not normal air in the gas tank, it's gasoline vapor.

The problem for the winter condensation in a boat tank theory is "How can this happen?" It simply doesn't.

Remember expansion and contraction takes place daily. Look at a 20L jerry can mid day and then on a cool night. The same thing is happening in your tank through the vent and although it’s a very small amount no arguing that it turns to liquid and settles to the bottom of the tank where the gasoline vapor is irrelevant.

 

[dreddnot]

I’m a year round boater (usually).

this year too much stuff happened and I did zero winter fishing. The last time I took my boat out was October 1st where I went for a super long run and went through a full tank of fresh gas.
So it’s been sitting in the driveway, at around 1/8 of a tank over the past 6 months. nothing added to it. I flush it with fresh water each time I use it.

what do I need to do to get it ready to use soon, just fill it with fresh gas and go?!
2021 Yamaha 115 with 24 hours on it. Had 20 hour servicing last fall.

thanks!

I would pull the spark plugs and put oil into the cylinders. then turn it over by hand 5 or 6 times. put plugs back in. run it for the season. Then before you put it away again pull plugs oil cylinders then old plugs back in. Fire it up in the spring and then pull replace plugs. as for gas just drain a little fuel off the bottom and add fresh fuel. That fuel is still good.

 

[Original]

Fill it up, and take someone fishing/prawning

Wink wink nudge nudge

 

[Foxsea]

Remember expansion and contraction takes place daily. Look at a 20L jerry can mid day and then on a cool night. The same thing is happening in your tank through the vent and although it’s a very small amount no arguing that it turns to liquid and settles to the bottom of the tank where the gasoline vapor is irrelevant.

I suppose if you have a day tank in the sun but we are discussing winter conditions and I believe, built in tanks. I doubt there's much going on with expansion/contraction as compared to the example you presented. The tiny amount of moisture in discussion is held in solution by the ethanol present even in mid-grade gas.

 

[Stizzla]

I just went out and put 70l of premium in the 80l tank.

I’m going to charge the batteries, clean her in and out and get on the effing water by the end of the week. Can’t wait to test out the new stereo and twin Garmin screens!

 

[dreddnot]

I just went out and put 70l of premium in the 80l tank.

I’m going to charge the batteries, clean her in and out and get on the effing water by the end of the week. Can’t wait to rest out the new stereo and twin Garmin screens!

the best purchase i made for my boat is the noco genius 2x 5amp charger. plug it in year round it will pay for itself with 100% battery life.

 

[Brando]

I suppose if you have a day tank in the sun but we are discussing winter conditions and I believe, built in tanks. I doubt there's much going on with expansion/contraction as compared to the example you presented. The tiny amount of moisture in discussion is held in solution by the ethanol present even in mid-grade gas.

It’s amazing how much materials will expand and contract even in the winter. We cut pipe at certain times of the day and install accordingly makes a very big difference especially when the sun comes out. I have seen guys continue to cut and try to install a “pup” as the weather warms struggling to get it to fit as materials expand only to have the temp drop and all the sudden it’s too short. Same thing is happening in the tank it’s breathing inhaling/exhaling as temps change sometimes not much sometimes a lot over the course of 6months in our climate you get such a wide range of weather. Have also filled a tank on a cold day and had fuel puking out the vent in my driveway when the sun came out the following day no joke fun times it was a considerable amount I had to siphon some fuel back out of the tank.

 

[dreddnot]

It’s amazing how much materials will expand and contract even in the winter. We cut pipe at certain times of the day and install accordingly makes a very big difference especially when the sun comes out. I have seen guys continue to cut and try to install a “pup” as the weather warms struggling to get it to fit as materials expand only to have the temp drop and all the sudden it’s too short. Same thing is happening in the tank it’s breathing inhaling/exhaling as temps change sometimes not much sometimes a lot over the course of 6months in our climate you get such a wide range of weather. Have also filled a tank on a cold day and had fuel puking out the vent in my driveway when the sun came out the following day no joke fun times it was a considerable amount I had to siphon some fuel back out of the tank.

3 teaspoons per gallon. you fuel is good for 8-12 month with octane 91 ethanol or not. I recommend 91 octane from shell for the winter weather it be 3/8 or half a tank. Then just add 87 in the spring. this is why you change the water fuel separators as water sits in the bottom and fuel flows overtop. say you have 85 gallons thats maybe 5 tablespoons and it would be absorbed. never had water issues.

 

[Ringo]

I just went out and put 70l of premium in the 80l tank.

I’m going to charge the batteries, clean her in and out and get on the effing water by the end of the week. Can’t wait to test out the new stereo and twin Garmin screens!

Check your Racor filter and don’t forget to add Seafoam to your fresh gas. That stuff is really good. I add 1 bottle/200L of gas every time I fill up and I only run marine grade gas which I believe is still ethanol-free.

 

[Foxsea]

It’s amazing how much materials will expand and contract even in the winter. We cut pipe at certain times of the day and install accordingly makes a very big difference especially when the sun comes out. I have seen guys continue to cut and try to install a “pup” as the weather warms struggling to get it to fit as materials expand only to have the temp drop and all the sudden it’s too short. Same thing is happening in the tank it’s breathing inhaling/exhaling as temps change sometimes not much sometimes a lot over the course of 6months in our climate you get such a wide range of weather. Have also filled a tank on a cold day and had fuel puking out the vent in my driveway when the sun came out the following day no joke fun times it was a considerable amount I had to siphon some fuel back out of the tank.

Good observations, Brando. What are your thoughts on closing the tank vent, just for winter storage?

 

[dreddnot]

Check your Racor filter and don’t forget to add Seafoam to your fresh gas. That stuff is really good. I add 1 bottle for every 200L of marine grade gas every time I fill up and I only run marine grade gas which I believe is still ethanol-free.

seafoam is a fuel stabilizer used to run it with my mercury 18xd. it works for that purpose. some say its an alcohol but alcohol is good for keeping water in suspension.

 

[Ringo]

Get the marine pro. Keeps your system clean.

 

[Brando]

Ethnol will separate from gasoline when too much water is introduced it’s called phase separation.

I don’t think you’d want to close the tank vent and stop this process the system is not designed for that in theory you could have pressures exceeding the 3psi that it’s tested to if you had a really big temperature change. Just be mindful that it’s possible and drain the separator that little bit of water that’s picked up in the bottom of the tank from time to time is isolated there and can easily be drained. It’s a good thing means the systems working as it should.

 

[dreddnot]

Ethnol will separate from gasoline when too much water is introduced it’s called phase separation.

I don’t think you’d want to close the tank vent and stop this process the system is not designed for that in theory you could have pressures exceeding the 3psi that it’s tested to if you had a really big temperature change. Just be mindful that it’s possible and drain the separator that little bit of water that’s picked up in the bottom of the tank from time to time is isolated there and can easily be drained. It’s a good thing means the systems working as it should.

were talking about maybe 6 table spoons. phase separation with only occur with a very very long time. Lets say you have 10% ethanol. 3 teapsoons per gallon. thats how much your fuel will hold. its not going to happen. if you add stabilizer youre covered. half tank is the most I would add. screw the full tank bs. you think your fuel is going to phase in 6 months. Wont happen. add stabilizer or 91. youre good.

 

[Brando]

I prefer to keep the tank full and avoid ethanol for winter storage you can do what you want with your boat. Will happily burn 87 when I’m using the boat often.

Three Ethanol Myths Clarified

In the few years since ethanol began to be widely used in the United States, a lot has been written about its properties, the problems it's created, and how to best cope with its possible effects. It's time we get to the bottom of how E10 is affecting our engines.

www.boatus.com