Managing Ethanol in Gas

jcminnesota

Cadet
Joined
Jun 20, 2012
Messages
25
HI....I am buying a new 2013 Alumacraft Classic with a 20 gallon built in gas tank. I live in "iceland" (MN) and store the boat for about 5 months....and I use it maybe 2-3 times a month the other 7. I also fish in lakes that don't require much travel time (or gas to get where I fish). On top of that my Yamaha 70 is very fuel efficient. So bottom line is that the 20 gallon gas tank may last all season. My question for the forum is whether I should keep topping the gas tank off, or whether I should try to use all the gas up (at least to a reserve of 1/4) before I gas up again. I would feel better about topping the tank off so if I do want to go for a long run I will have plenty of reserve. Taking the boat out with 1/2 tank of gas would make me nervous. It seems that by constantly topping off the gas I am putting new fresh gas in that will mix with the "old" gas and keep it fresh. I also have heard that gas stabilizers can keep gas good for 2 years. (Thats what the Seafoam people recently told me). For those with built in gas tanks and not much boat use, what do you recommend? And what stabilizer is the best? Anyone aware of any tests of stabilizer performance?
 

theBrownskull

Chief Petty Officer
Joined
Jun 23, 2012
Messages
625
Re: Managing Ethanol in Gas

I have a mercruiser and I use a product called "quickare" and put it in the fuel everytime I fuel up. They claim it keeps the fuel fresh and I have not had any problems.

quickare.jpg

I then use Quickstor prior to winterization.

quickstor.jpg

There are other threads on this site that discuss fuel stabilzers.
 
Joined
Jun 17, 2012
Messages
940
Re: Managing Ethanol in Gas

I use Startron fuel stabilizer, but probably not necessary if your talking 6 months or less. I would also recommend that you use higher octane premium gas and keep the tank topped off.
 

acarter92

Petty Officer 2nd Class
Joined
Dec 25, 2011
Messages
198
Re: Managing Ethanol in Gas

Just buy a towable tube and find some kids... Problem solved, the tank will be empty by the end of the day :)
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,338
Re: Managing Ethanol in Gas

I have a 92 gallon main and a 54 gallon reserve tank. In season, I don't use anything. I run them down to 1/2 tank them fill them up for no reason other than 2 - $200 entries on the credit card look better than a single $400 entry.
:D
For winter, I use whatever ever stabilizer they have on sale at the time. Last year it was Stabil - Marine
 

tazrig

Lieutenant Commander
Joined
Dec 20, 2012
Messages
1,752
Re: Managing Ethanol in Gas

You are better off using up the old gas first and then re-fueling. The only major problem with Ethanol gas as opposed to the old MBTE gas is the following: Ethanol absorbs far more water than the old gas (MBTE) did but the ethanol gas and the water it absorbs is harmlessly passed through your engine. The problem with Ethanol comes in because it absorbs more water than the the old gas up to a point but then it suffers "phase separation" which is the water completely separating from the fuel so you have a layer of gas in your tank and a layer of water sitting below the gas in your tank. Once this happens they cannot be mixed back together. You have to drain out the water from your gas tank because after the engine sucks out all the gas it will start pulling on the layer of water and obviously engines can't run on water. So the sooner you can use the gas the better. Startron stabilizer:

http://www.iboats.com/Star-Brite-St...88623911--session_id.730052229--view_id.49210

works great if you're not going to be using your boat for several weeks or more but no stabilizer will stop Ethanol from absorbing water and eventually suffering "phase separation". That is why you top off your tank for winter storage so there is less air (moisture) in you tank for the gas to absorb. If you put in some type of stabilizer (which basically just keeps the octane level up) to keep the gas fresh and run down your tank to 1/4 between refills, and remember to stabilize and top off in the winter you will be fine.
 
Last edited:

roscoe

Supreme Mariner
Joined
Oct 30, 2002
Messages
21,758
Re: Managing Ethanol in Gas

20 gallons of gas, 4 hours of full throttle operation, or 7 hours of 3000 rpm operation.

I often leave the dock with less than 6 gallons of gas for my 115 hp Merc.
Same for the other boat with a 75 hp.
But I keep a 2 gallon reserve tank for safety sake.

Personally, I would not keep the tank full.
3/4 max, then let it run even lower after Labor day.

I use Seafoam as a fuel system cleaner/maintainer, and Stabil year round, cause with 4 boats, I never know when the last fuel fill of the year will be for each boat.
 

JoLin

Vice Admiral
Joined
Aug 18, 2007
Messages
5,146
Re: Managing Ethanol in Gas

I have a 92 gallon main and a 54 gallon reserve tank. In season, I don't use anything. I run them down to 1/2 tank them fill them up for no reason other than 2 - $200 entries on the credit card look better than a single $400 entry.
:D
For winter, I use whatever ever stabilizer they have on sale at the time. Last year it was Stabil - Marine

Ditto that. I always use Sta-Bil, but follow the same method.

jcminnesota, there are a gazillion previous threads about ethanol in this forum. You'll find there are 2 distinct 'camps'... those who believe ethanol is a major concern, and those who believe that it seldom causes issues.

I believe that while ethanol can contribute to problems in gasoline that lies stagnant for a long time, it's a convenient scapegoat for all kinds of issues that aren't the fault of the fuel.

I treat whatever's in the tank before winter layup and run the motors long enough to insure that stabilized fuel makes it through the entire fuel system. Never had an issue the following spring. If you're concerned about yours lying around for too long, Sta-Bil has been around forever and has a good track record.

My .02
 

ENSIGN

Lieutenant Junior Grade
Joined
Jun 21, 2009
Messages
1,179
Re: Managing Ethanol in Gas

If you don't have a water separating fuel filter on the boat by all means get one! You can check around and see if non ethanol gas is available in your area.I know it's sold here in Maryland.
 

phonfish

Cadet
Joined
Aug 26, 2008
Messages
23
Re: Managing Ethanol in Gas

+2 on the startron.
Remember this, you can't overdose it with fuel stabilizer.
Just my opinion: If I had a small tank, I would leave it empty or near empty. Water in the fuel tank will be caught by the water separating filter, but phase separation happens thru out the fuel system, not just in the tank . I suspect the biggest culprit is the vst tank on most outboards. Since the fuel sits there with only one filter to catch the crud, along with the injectors, need to be cleaned.
Another way to look at it: 100gals sitting, experiencing phase separation is worse than 5 or 25 gal sitting.
Bottom line is to use it or eventually PS will get you.
 

Oshkosh1

Ensign
Joined
Jun 8, 2009
Messages
968
Re: Managing Ethanol in Gas

Throw some seafoam in it and go fishing during the season, drain the tank and use it in the snowblower/sled/car during the winter. Start with fresh gas in the spring.
 

jcminnesota

Cadet
Joined
Jun 20, 2012
Messages
25
Re: Managing Ethanol in Gas

Thanks to all so far. I will plan to use Startron on every fill up...but I would ask those that responded with a +1 or +2 what they meant. Is that good or no so? If not so, then what stablizer do you use? I have used Marine Stabil in other boats, snow blower, mower since it advertises that its stronger than regular stabil but many on this forum recommend Startron so I thought I would try it........also another followup question for the forum relates to mixing no alcohol premium gas with Ethanol gas. I have a number of stations close where I can buy premium unleaded gas with no ethanol. Can I use in my boat? Will it store better without Phase separation? Can it mix with ethanol gas on occasion? I ask this because we visit resorts up "north" that only have gas stations with ethanol gas. I would only need to do this occasionally but I have read on the forum some opinions that Ethanol and Non Ethanol gas don't mix well....and can form some kind of gel/sludge. Any one have definitive up to date opinion on this?
 

theBrownskull

Chief Petty Officer
Joined
Jun 23, 2012
Messages
625
Re: Managing Ethanol in Gas

A +1 means that the person agrees with what was written. A +2 just seconds the opinion.

I have used marine stabilizer in my snowmobiles, snowblower, lawnmover, etc.

I have only run ethanol gas so I don't know about the mixing. Maybe someone else has better info.
 

agallant80

Commander
Joined
Oct 25, 2010
Messages
2,328
Re: Managing Ethanol in Gas

I did not read through all of the posts I am sure there is a bit of a "it will be fine" or "Your boat will rot in flames if you do that" debate going on. I will just reply back with what I do. I have a 48 Gal tank on my Stingray 215LR. I always fill up when it hits the 1/2 mark (Don't want to be cought out there with low fuel). Last summer I filled the boat twice so one half of a tank both times. I filled the tank a third time when I put it up for the winter and put in the proper amount of stabalizer.

One thing that I do is I will crank the boat over and let it idle for about 5 sec every 8 weeks or so when it is in storage. I don't want to destroy injectors by letting them sit with ethnol fuel. I don't know if this makes me crazy or of I am doing something smart.

Never had an issue with bad gas. I think it takes the fuel a lot longer to go bad then most people think but when you look what we are talking about here a boat which is every ones toy/pride and joy people tend to go a bit over and beyond when it comes to those things.
 

jcminnesota

Cadet
Joined
Jun 20, 2012
Messages
25
Re: Managing Ethanol in Gas

Thanks...while on how the forum works, how do you embed a photo and put the footnote on your boats like on your forum response?
 

NYBo

Admiral
Joined
Oct 23, 2008
Messages
7,107
Re: Managing Ethanol in Gas

Thanks...while on how the forum works, how do you embed a photo and put the footnote on your boats like on your forum response?
Click on the "Settings" button to the right of "My Profile". In the column on the left under "My Settings" are buttons to "Edit Signature" (the stuff at the bottom of each of your posts) and "Edit Avatar" (the little picture below your screen name in each post).
 
Top