Mixing 10% ethanol gas with old gas

[blacksburg3292]

I am far from an expert on this but I live in Virginia and all of our stations just went to 10 percent ethanol gas. I have an 89 sea ray with a 150 Mariner and I had half a tank of old gas and filled the other half with the 10% ethanol gas and I took it out. It ran like a champ the first 1/2 mile and then cut off, would hardly start and I had to limp it back in. I dropped it off at the repair shop and took my freshwater boat. It has a 50 horse yamaha. I had a 6 gallon tank with 3 gallons of old fuel and I filled it with 3 more gallons of the 10% and I had the exact same result, I mean exactly. I emptied out all 6 gallons and filled the tank with 6 gallons of the 10% ethanol fuel and the motor ran like new for hours with no problem. I picked my other boat up from the shop, drained the fuel and added all new 10% ethanol and it also ran like a champ. I'm writing this to let boat owners know that this gas definately doesn't work with the old gas in the same tank but used on its own seems fine. I don't know about the other effects such as eating fuel lines, etc...If anyone else has had this problem please let me know. Thank You.

 

[KM2]

Re: Mixing 10% ethanol gas with old gas

The only logical explaination I can think of is your old gas had a lot of water in it.

 

[ob]

Re: Mixing 10% ethanol gas with old gas

I'm thinking the operable word here is "old gas."How old? Old enough and it's lost its original potency.I'm thinking you just had 50% bunk fuel and 50% percent good fuel which didn't equivilate to good fuel.However I can't speak of the compatibility of blending the two grades.My guess would be that there wouldn't be problem if bith were fresh to begin with.

 

[Major Woods]

Re: Mixing 10% ethanol gas with old gas

Your old fuel is suspect not the fresh fuel.

 

[Silvertip]

Re: Mixing 10% ethanol gas with old gas

Agreed. The old gas is the culprit. We in the midwest have used blended fuel for years. My boat sits from mid November until being awakend in April. Never had a fuel related problem with this or any of my other engines.

 

[Texasmark]

Re: Mixing 10% ethanol gas with old gas

Agree also. If you have old fuel, drain it out and replace with fresh; definitely on an annual basis.<br /><br />Not sure as to the cause of your problem. Would think that if the ethanol mixed with water it would make a blobby goo and that goo would attempt to go thru your fuel system. I'd think that the fuel filter screen would be small enough to keep the water molecules out. So if you had any kind of a problem it would be lack of fuel because the fuel filter was clogged up.<br /><br />What you didn't say was did you run the boat(s)on the old gas before you "filled up" and did it run ok? Gonna bet the answer is no.<br /> Bet you were going out for the first time for the season (both boats) and the old gas is what got you .<br /><br />My 2c.<br /><br />Mark

 

[cobra 3.0]

Re: Mixing 10% ethanol gas with old gas

Did you empty the fuel bowls on the carbs last fall? I'd suspect varnish in the carbs. The ethanol may have dislodged the gummy residue and caused it to gum up the carb even more.