ethanol issues

[rhody jim]

Having read this and other internet forums for the last eight years I thought it might be time that I might have something to contribute which may have some value to the A4 community.
This season has been a bummer for me Re: water in fuel. My boat is a 1980 Catalina 30 and it is now time to pull out the gas tank and either clean and reinstall or replace, depending on what I discover. Options will include 18 gallon aluminum or polyethelene or go with a smaller tank.
During my lengthy readings over time on this horrible product E10 it is noted that water is not nearly so much of a problem for automobiles since when the ignition is not on the vent is not open.
Would it not be the simplest of solutions to install a valve at the vent line at the fuel tank and as part of your starting procedure to open the vent valve as well as the fuel valve prior to turning on the ignition. and subsequent to shutting off the engine, close the fuel and vent valves. Thus not leaving the tank open to the atmosphere for days on end in a very humid environment.
Am I missing something here ?

[JOHN COOKSON]

This Has Been Kicked Around In The Forum A Bit

Install a cylinder filled with calcium chloride or some other desiccant in the vent hose and change it regularly. As I recall there are some type of crystals that change color as they adsorb moisture.

TRUE GRIT

[ndutton]

Jim,

How did you conclude the vent was the source of the water? Where are you located? Do you typically keep your tank full? Where do you get your boat fuel?

[thatch]

"Filler O ring"

One other thing worth mentioning, particurlarly on Catalina 30's is the "O" ring on the fuel fill cap. While washing mine, I noticed that the area around it becomes completely flooded.
Tom

[rhody jim]

o-ring is in place.... could it be worn ? sure...no harm in replacing----during summer months when cap removed for filling inside of cap usually shows condensation and I wipe out same---tank always kept full while on the hard... have owned boat 8 years.... regular pump gas used exclusively during that time with MMO and Stabil added at recommended amounts 1oz per 2.5 gals for each. Got brainstorm re. closing vent when not in use after watching several videos depicting what was happening to e-10 when put in a metal container exposed to the atmosphere for very short periods of time and given the reason that late model automobiles are not affected due to vent being closed when not in use.....dessicant idea deserves some pondering.

[Administrator]

Always full while on the hard...

I've always wondered whether this was the solution, or the problem.

I know the opinions are all over the place, but my strategy is to never have too much fuel and never too little.

Bill

[CalebD]

Expansion and contraction

When my boat sits on the hard from Nov. - April the temps vary up and down; sometimes quite a lot in one day. Colder temps make the gas in the tank shrink slightly in volume and hotter daytime temps make the gas increase in volume. Without an open air vent, where will the gas go?
With a sealed vent if the gas is warmed and expands it will be forced into the carb if the fuel line is not shut off. If the fuel petcock is closed then the gas tank and line will be under pressure. In colder temps the tank would be in a state of vacuum, or negative pressure. I'm not sure I want to subject my old gas tank to varied pressures like that. I'm happy that it holds gasoline without leaking.

Nope. Not for me or my 45 year old Monel tank. I'll settle for having to pump the damned thing out every X number of years to get the dirty last bottom bit of E10 crapola out of there. This is what 10+ years of unattended E10 madness looks like:

[JOHN COOKSON]

Sounds Like The Smoking Gun To Me

-during summer months when cap removed for filling inside of cap usually shows condensation and I wipe out same---

How do you get moisture inside the fill cap? Is it water? If so how did it get there? Sounds to me like you need a new gasket or a whole new fill cap fitting. I'll bet the vent line is a "red herring".

TRUE GRIT

[roadnsky]

Install a cylinder filled with calcium chloride or some other desiccant in the vent hose and change it regularly. As I recall there are some type of crystals that change color as they adsorb moisture.

TRUE GRIT

http://www.h2out.com/products

[Cool Beans]

But can the fuel really absorb that much moisture from the air over a short time? How much water that we end up in the system is from humid air getting in the vent line?

Gasoline is constantly evaporating, even in cold weather. . .and gas vapor is heavier than air so I would think it is constantly displacing any atmosphere out of the vent. . .

Just a thought. . .

[ndutton]

In vented tanks, you can't get humid ambient air inside when there's no space for it to occupy. Without humid air there can be no water condensation. It's on a sliding scale, less air volume in the tank means less potential condensation, an empty tank gives the greatest air volume and therefore the greatest water condensation potential.

My Dad worked for Douglas and later McDonnell-Douglas Aircraft his entire life. I remember him explaining this reasoning and it was even done on the flight line at the factory.

Some aircraft stored at the airplane graveyard facility in Tucson (AMARC) are mothballed or 'pickled' for future return to air service. These planes have their tanks drained of fuel then filled with heavy oil.

[edwardc]

But can the fuel really absorb that much moisture from the air over a short time?

A few seasons back, I got a demonstration of how fast E-10 can absorb water from the air. I was working on my carb, and set a pan filled with drained, clear gas out on the dock to get it out of the boat. It was a slightly foggy day, and I was amazed when, fifteen minutes later, when I went back to dispose of the gas it was cloudy white with all the water it had absorbed!

[rhody jim]

lots of well reasoned replys which are much appreciated..... condensation in cap in summer is H20.....pumped out about 6 gallons yesterday after filtering so as to mix with fillups of other vehicles rather than a trip to DEM for disposal...... filler cap was dry inside yesterday hadn't been opened since october 5, certainly has rained since then. I'm still wondering why automobiles have a closed system when not in use.

[joe_db]

Cars have sealed fuel systems to meet hydrocarbon evaporation emission requirements. They aren't totally closed or they wouldn't be able to run, but the air going in and out goes through a filter of some kind. I read once a 1965 Mustang SITTING PARKED TURNED OFF pollutes more than a modern car that is RUNNING.

My two solutions to this issue, depending on my energy level, are either to just use Startron and keep the tank full during the winter or change over to Avgas in the fall.

[Cool Beans]

In a pan with a lot of surface area, all that direct contact with moist air. . .I can see a bit of water being sucked in. . .but I was mostly talking though the vent line. . .not saying it can't happen, I ain't no expert

I wonder if it would be pertinent to add another preventative maintenance item to our to-do lists? That of just maybe twice a year sucking out the tank clean and filling with fresh gas? That way that 1/4" of water or whatever in the bottom of the tank doesn't continue to build up over the course of many top off's and fill ups and cause problems?

That's the route I plan anyways. . .just a thought