Marinette Boat Forum

Bill, sorry to hear about the Admiral's lost boating season.

I didn't think Seafoam had any preservative properties at all, rather that it was a varnish solvent. I am guessing that your fuel will lose octane based on my experience with my Airstream. It runs like crap on low octane gas and that's what happens when I try to go on last year's fuel. Adding some fresh high octane to the tank makes it run fine. On the other hand, my 318s run fine on last year's gas based on me having to cruise to the gas dock every launch. I've always added a little Stabil to the tanks on the last run of the season and leave the tanks 20% full. On my outboards there is a carb problem if last season's gas is left in there without some Stabil.

How did you get the tanks filled this year if you never launched the boat this year?

Leaving a fuel tank 80 percent empty is inviting condensation and accumulation of water in your fuel.
If stored on the hard even worse. Most marinas require full tanks to reduce chance of explosion.

safe boating
dave

Not addressing the explosion question (which I agree is a valid concern), let's go to an expert source. Here's a quote from a lengthy Boat US piece on the subject: With a full tank, there's no room for condensation to form so there should be no water for the ethanol to absorb. The more room there is in the tank, the more surface area there is for condensation formation and the less ethanol there is to absorb the resulting water. Cycling temperatures from warm to cold also increases the amount of condensation. Finally, ethanol cannot absorb as much water at low temperatures as it can when it's warmer, so the gasoline will phase separate sooner in colder temperatures (see chart below).

Once phase separation occurs, there is no way to reverse it. No additive can rejuvenate bad gasoline despite advertising claims to the contrary. Bad fuel is bad fuel, and the only options are to dispose of it or recondition it.

Seafoam - good for stabilizing gas in tanks against breakdown, varnishing. Not so hot for water in gas. That's why I'd filled in March. To eliminate any space in tanks for condensation to accumulate. Admittedly, the period between Oct. 2016 and March 2017 without full tanks may have caused some issues, but I'd taped over the tanks' vent outlets to prevent any "breathing" (warm/sunny weather = increase in tank pressure which would've caused air in tanks to be "exhaled". When night fell/cold weather - air in tanks would've contracted, drawing in air and potentially increased water vapor/condensation.). Full tanks also greatly reduce chance of combustion/explosion. There wasn't anything running on the boat other than 45w solar charger connected to batteries to maintain battery charge.

Dave / Joel,
Your (or anybody else, I'm equal opportunity listener ) thots on current gas's viability? I'm thinking guys, that your comments lean to "leave the tanks full till next year at least". What about thereafter? Use on boat with an infusion of high test gas and/or octane booster?

Thx,
Bill

If you didn't have crud-in-gasoline issues this summer and you check filters you are probably doing as well as can be expected in that department. This winter, leave tanks full, BoatUS urges. Taping won't help much in my humble opinion because the air already in tanks is moisture laden and that moisture will condense with temp changes. And there will be air leaks to replenish the supply. I cannot comment on the difference between Seafoam and Stabil except that I used Seafoam occasionally to clear carb and Stabil to maintain stability of fuel against disintegration. Hey, if it will work, use both. Cheap "protection"

On the full gas tank thing, my marina is OK with it not being full. Their big concern is that a really full tank will maybe spill if the boat swings in the travel lift. Anyway, at the refinery they taught that tank explosions happen in fires, and the tank will not blow as long as there is still liquid in it to boil off. If it is the breathing that concerns, there will be the same percentage mix of air to gas in and 80% full tank as there is in a 20% full tank sitting side by side in the same environment. Just my thoughts, I don't mean to contradict anybody.

On the condensation issue, I accept that there is more breathing with a not so full tank. I have water separators inline that I drain and clean each spring after the boat has run for a little bit. I've never had a problem starting the engines or had the water separator overloaded. I don't generally use alcohol/gas mix so pretty much any condensation is at the bottom of my tank. Tape on the vent I don't think will seal against pressure difference (which causes the breathing). It will keep bugs from building something there though, which is a good thing. You don't want to block the vent off anyway, it is there to prevent pressure from building in the tank, which can make gas more likely leak into the bilge.

The BoatUS piece implies that any water separating out from the gas makes the gas "bad". I don't want to be argumentative, but this makes no sense to me.

Phase separation has been a problem with the introduction of ethanol in gasoline.I can't define it. But I know that "stale" gasoline, where the water separates from the fuel and drops to the bottom of the thank...along with resulting gunk (and that's what it looks like), clogs carbs. From a cost of repair business it is a big item as it is for safety. Why safety as an issue? Because engines that quit when you need them result often in unsafe situations. Stabilizers slow the process and keeping water out of the tank goes along with keeping the gasoline fresh.

As I think about it, I'm not clear on why ethanol was introduced other than it's a cheap(er) way to extend the supply of oil and will burn good enough. It may be environmentally better. And, of course, the corn farmers profit -- a way to "burn off" their excess production.

Finally, I'm puzzled about the percent of air to gas reference above. Less liquid in the tank means more air. Air holds water which condenses and falls into the tank in cooler temps. Water in the tank is not good.

I'd make sure the tanks were truly full and leave it that way. You have lots of stabilizer in there already.

Sorry to hear of your wife's injuries. Sounds horrible.

Jeff

Thanks guys for commenting on my issue. The tanks are 100% full / much Seafoam added, so I'll leave as is.

Also, thanks for the nice thots on Admiral's late spring / all summer issue. I'm recoup'ing from left hip replacement surgery a week ago (when it rains, it monsoons around here). So I won't be back down to the (already blocked) boat for about another month.

Bill

There should not be an ethanol problem because it should not be used in your boat, small engines or collector cars. My marina supplies ethanol free mid range gasoline which works well in the Marinette. I will top it off with High Test before I store it. My Ford sedan gets a lot of use with regular enthaol gas but when I store it for the winter I top it off with ethanol free and stabaliser. My GMC diesel 4x4 is all I need for the UP winters.