First tank of ethanol this coming week.... suggestions?

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Well-known member
Feb 17, 2006
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Normandy Beach, NJ
Since buying my boat last September, I have used a little over 1/2 a tank of gas (about 75 gallons). It is time to fill up.

I am going to a pretty high volume marina on the water for gas, and I am hoping that they have gone through a tank or two of 10% ethanol. Anything I should add to my tank? I plan on ringfree, but was wondering if there are any other things you guys would do? I have heard that it is not ideal to mix MTBE and Ethanol gas, so hence my question....

Local marinas here were not filling anyone with e10 unless they were under 1/4 tank of MTBE fuel. I would wait intil you are down 115 gallons if you have the 150 tank.
I'm going on a run and gun fishing trip this weekend, specifically to burn down the MBTE enhanced fuel before I get my first E-10 load.

Since I have a Yam fuel flow meter on each engine that gives port, starboard, and total fuel burn I'll be watching those to ensure I'm down to about 20 gal before adding the E-10. Those Yam meters have been very close, e.g., when they say I've burned 98 gal, I actually fill with 96 gal. Even the small error is on the safe side.

Here is what I'm going to do. Burn off about 40 gal chasing the birds and breaking fish to get me down to about 20 gal. Change the nice 10 micron clear bowl filters for the older OEM Mercruiser solid canister filters (also 10 micron). Add about 20 gal of E-10. Go out and run up/down the Pax river jumping big boat wakes and generally sloshing things around to burn off about 20 gal. Remove the Mercruiser filters and toss them. Install the 10 micron clear bowl filters I removed earlier in the process. Fill up with E-10. Go back to fishing.
I do know of people who are running Racors, and who filled up 40gals or more of E10 on top of 40gals or more of MTBE fuel and haven't had any issues.

I do believe that (1) having a Racor and (2) buying E10 fuel from a place that properly cleaned their tanks is the key to avoiding issues ...
FWIW, I read somewhere that to avoid problems with mixing E10 and MTBE you want to add at least 4x as much E10 as you have remaining MTBE in your tank.

I also added a bottle of Startron fuel treatment (scattered reports of helping with Ethanol problems) when I did my first E10 fueling. I was down to about 10 gallons of MTBE and added 45 gallons of E10.

If you have any water in your tank, you definitely want to remove or treat that problem first.. adding E10 to a mix of water and MTBE can make bad things happen :)

I've burned through about 175 gallons of E10 so far on my 1999 Yamaha without any problems so far. I have a Racor F/W seperator installed.

-- Tom

If you've only used a little over 75 gallons since last September, I'd be careful about filling it completely full of E-10. At your burn rate, it is unlikely you'd use another 75 gallons until you put her up for the winter. Which means you'd still have a belly-full of E-10 to over-winter with.

From what I've heard, we are being advised to go into the winter sleep with as little of this E-10 as possible on board because it doesn't have a great shelf-life, even with stabilization.

Anyone else planning to store on an empty fuel tank this winter?

I did my first E10 fill on 6/29. I was trying to run out the winter mix I had and thought I was lower than I was (no Flowscan and the dash guage not so precise), but when I filled I topped off at 60 gallons. So, I'm starting with about a 60/40 mix, new to old. I've run only about 3 hours (I drift fish a lot) with no problems but now the boat has been sitting as I have not been down that way for 2 weekends, and I'm sweating what I might find.

My first order of business will be to somehow remove my current stuck seperator filter and dump the contents to see what I might have. If it looks and smells OK, then business as usual with a bit of caution. If I see the goo, then I've got a problem and will have to figure out what's best to do next. I've heard that if there's a reaction between the fuels in the tank, it will have a funny smell so I'll probably give it a quick sniff test. Not sure what I'd be sniffing for, but I know what gasoline smells like.

If I can find it, I'll treat with Startron for this season. I always use Ringfree and I'm sure there's still some Stabil left in the tank from my winter mix. I'll be replacing filters more often (I've got 4 Sierra's on board plus a Racor type with a see-thru bowl), probably every few weeks dumping the contents for any give-away signs of the filter clogging goo that might form or seperation of the fluids. Hopefully I can make it through 2 more fills without an issue but at the rate I'm going this year, that could take the rest of the season.

Good luck

John S.
My boat was full (126 gallons) at the beginning of the season and I guess I ran the gas down a little less than 1/2 tank before adding gas around April 1. As of now I have burned about 250 gallons total for the year and have not had any issues. I have replaced the fuel separator 3 times and it has looked good every time. :D The motor is a F225.