How to prevent Gasoline/Ethanol related issues

[ktm_2000]

Hi All,

I wanted to ask this question on PSChauss's carb rebuild thread but though it deserved it's own topic - How to prevent needing a carb rebuild?

With the introduction of ethanol, my experience has been lots of issues with condensation and the vent lines going to the fuel tank. The results have been lots of fuel filter checks and draining and a few carb rebuilds over the years.

I've heard newer fuel injected systems are less likely to have issues, but they probably are quite expensive to repair if they occur so I would rather do prevention than repair.

Here's my plan as of right now
1. Vent line rise - add as much rise as I can to prevent water from going up the vent line - I currently have the vent line running as high as I could under the gunnel - about 9" of rise over the vent itself.
2. Vent facing backwards - again no water migrating up the vent
3. fuel fill gasket - check make sure it is sound
4. 2 fuel pickups in fuel tank - make sure one doesn't get clogged
5. 2 separate lines going to fuel filter - valves and setup to switch as needed
6. Fuel filter above deck and in a place where I can easily visually check and drain as needed - yes it will be ugly above deck and could get knocked but I would rather have piece of mind that I could easily inspect and drain if needed. Plus, If I carried extra filters and plastic drain bowls if it did get damaged it would be unlikely that the mounting point would be damaged.

I'm wondering what others have done to help prevent issues from occurring? is there anything else I could plan on doing? is there something I could put inline with the vent to reduce condensation?

thanks in advance

[Rawleigh]

On a rebuild I did on a 30 Scarab Sport we molded a recessed box out of fiberglass that had the fuel filter recessed in it. It was flush mounted in the front of the rear seat and had a teak trim molding around it with a smoked plexi door. It looks and performs great to this day. Any spilled fuel will drain into the cockpit, the filters are easy to change, and in an emergency you can drain the filter bowl in rough conditions without the risk of blowing yourself up. The plexi door keeps the filters from rusting.

[Stephan]

Matt-
I am just down the road from you in RI.
I have not gone to the lengths you describe but do have a nice high vent line and good gasketing.
My concerns for water have centered around getting bad gas and condensation inside the tank.
Each season I have gotten the fuel level as low as I can for storage and have used the sender unit installation port as a way to get a look inside the tank at the start of the year. This year after being out for the water for several seasons I did find some water and was able to pump it out before filling with fresh fuel.
Finding places to buy gas early/late in the season can be a challenge. I just paid $0.35/gallon more because I believed the seller had good equipment and was selling a good amount of gas (since the last rainfall!).
I do carry 4 spare fuel filters with me just incase.
Best defense I know of is to burn it quick and run it often.
Good luck,
Stephan

[ktm_2000]

Rawleigh,

less elegant from what you've done - I will mount the fuel filter on the starboard side of the storage module on the transom, it will be tucked in but still visible from this viewpoint. The filters will probably rust but if I change them out yearly it shouldn't get to a point where it causes an issue.
https://photos.app.goo.gl/WsyCCxMEEysAkhjs7

I got the powder coated filter mount so that should last for quite a few years
https://www.defender.com/product.jsp?id=133972#

Stephan,
Since she will be a trailer queen, I will get gas from regular gas stations, I think the key is to buy from high volume places, I have gotten a bad batch before from one place - took out my truck and boat, so even that plan isn't great.

[HotSpot]

I’m in precarious spot of having gas engines and the original fiberglass tank. Reliance on trusting that premium ( high octane) gas in WI contains no ethanol is my strategy. Long term, I know these motors are on their way out having served 30 years, so if they get messed up, we refit the tanks and repower. Although, I do hope for a few more years.

Is there a quick way to test for ethanol at fill-up time? I always fill jerry cans at the gas station. I’m afraid the distributor may inadvertently fill the premium tank with an ethanol grade some day.

[Bruce]

Matt,
All those things you mention will not prevent moisture absorpion in the fuel with ethanol.
As long as the tank is open to the atmosphere, its going to absorb moisture with ethanol.

The E85 performance engines I build have issues too runnning Holley injection. Forget running pure methanol and the issues it causes.

Don't put the vent line higher than the fill cause when you fill it will back up thru the fill and not the vent line at full.

Just by Recreational gas that has no ethanol.

In 29 years of boat service, water in the fuel was a minor occurance. Carb rebuilds were more common with old fuel and junk.

[Carl]

Is there a quick way to test for ethanol at fill-up time?

Yes, but if you can wait a few minutes you can buy an inexpensive reusable kit to check. Its simple a graduated test tube that you add water to a mark, then fill to a higher mark with the gas your testing, shake and wait. When it settles you check the waterline. If it rose higher the gas has ethanol (ethanol mixs with the water). The purchased kits will also indicate what % of ethanol the gas had.
You do not have to buy the kits as you can use a regular test tube, clean class bottles or jars...but then you have to get the right proportions and won't know how much ethanol.

[Sheer Folly]

After replacing the fiberglass tank on my Bertram33 FBC with an aluminum one, I was still concerned about the ethanol phasing out and creating a very corrosive condition in the bottom of the tank.

My solution was to design and build a vent line filter that used a desiccant to filter any moisture in the air coming in, or out, of the gas tank.

I used a “molecular sieve” desiccant, over “silica gel”, because it has a lower due point. It seems to work well as I have seen no indication of water in the fuel that I save from the engine and generator fuel filters changes to check for water settling out. I also use Koloa Kit water finding paste to check for water in the tank, which I sometimes Winter store with as little as a 1/4 tank of gas.

[HotSpot]

Yes, but if you can wait a few minutes you can buy an inexpensive reusable kit to check.

Thanks, Carl. This seems like the right solution for me. There’s usually plenty of time between filling up the cans and heading to the boat. If it doesn’t check out, the gas could go into the lawn mower and truck.