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Retired Air Force
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Discussion Starter #1
Just tested my fuel (some bought months ago and some bought yesterday from the same place) and it showed 10% gasoline! I have had a lot of trouble tuning in 2 NA engines. Both want to die after a pass but will re-start after 30 seconds and run OK and both are garbely in the mid range but seem ok at top end. From what I have read E90 would cause a lean condition as compared to E85. Both engines were dynoed and ran OK there but in the boat had trouble. Maybe the dyno fuel was E85 while the boat had E90? Could this be the cause to my problems?
 

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Just tested my fuel (some bought months ago and some bought yesterday from the same place) and it showed 10% gasoline! I have had a lot of trouble tuning in 2 NA engines. Both want to die after a pass but will re-start after 30 seconds and run OK and both are garbely in the mid range but seem ok at top end. From what I have read E90 would cause a lean condition as compared to E85. Both engines were dynoed and ran OK there but in the boat had trouble. Maybe the dyno fuel was E85 while the boat had E90? Could this be the cause to my problems?
Its possible. Why not just add some 91 to it until it tests 85 and see if it improves. I would see how much gas you need to add to 1 gallon of the E90 to determine how much needs to be added.

I am really surprised it checks out that high. They can get in more trouble for being high on the percentage than if its low.



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Retired Air Force
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Discussion Starter #3
I checked it 3 times and each time the same results on both the older and newer bought fuel. It was actually closer to E91. Yes, I think I will return the carb to its original settings, add the gasoline and see what happens.
 

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Retired Air Force
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Discussion Starter #4
I am really surprised it checks out that high. They can get in more trouble for being high on the percentage than if its low.[/QUOTE said:
Gas Versus E85 - Converting To Corn - Popular Hot Rodding Magazine
This article says;
"Big Brother says the mixture has to be between 70 and 90 percent. With a late-model, fuel-injected car built to accept E85, the difference isn't noticeable, however, when a carburetor is subjected to this variance, it can't compensate"
 

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Its possible. Why not just add some 91 to it until it tests 85 and see if it improves. I would see how much gas you need to add to 1 gallon of the E90 to determine how much needs to be added.

I am really surprised it checks out that high. They can get in more trouble for being high on the percentage than if its low.
I agree with GN7 water it down and try it there...
 

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Gas Versus E85 - Converting To Corn - Popular Hot Rodding Magazine
This article says;
"Big Brother says the mixture has to be between 70 and 90 percent. With a late-model, fuel-injected car built to accept E85, the difference isn't noticeable, however, when a carburetor is subjected to this variance, it can't compensate"
WOW. I knew they gave them alot of latitude on the weak side, but never knew they let they get that rich with the ethanol.



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northern member
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Serg , do you have a oxy. sensor to tune with ? makes sense to richen with gas and jet down if the ethanol were to go below 85 . wish we had e85 in the pumps here !
 

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Last summer the e85 I bought tested e90 and a friend who buys his fuel in another city also got e90 early in the summer. I don't know the real reason it happened, but ethonal is cheaper than gas to the distributor. It makes you wonder how many times the e10 or pump gas is actually higher in ethanol too. It makes tunning a little hard when you get variations with the fuel. Does anyone check the pump gas (e10) for ethanol content?

I actually didn't know there was an upper limit on the e85 content, I only knew it could be as low as 70%.

(e85 user in TEXAS.)
 

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Retired Air Force
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Discussion Starter #9

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I actually didn't know there was an upper limit on the e85 content, I only knew it could be as low as 70%.

(e85 user in TEXAS.)
The reason they have to limit the ethanol content is because they are selling you fuel based on its energy content.

Imagine that every car in the country could handle any percentage if E-XX. No carb cars anywhere.
Now imagine you bought fuel thinking it was E25 or E50 and it was in fact E95 and fuel milage was crap. You were charged E50 prices, with the asumption that it was 50% gasolene, and the milage if 50% gasolene. But instead, you got E95, and shit milage. Imagine if they were allowed to do that to 10 million fill ups a day.

You have to stop thinking like boater, and thingking OH BOY! horsepower!! And think like a pissed off soccer mom that just found out she has blown this months fuel budget on 3 fill ups.



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Highaboosta
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It's doubtful that 5% difference in the ethanol ratio would make a noticable difference in how the engine ran.
The base tune was probably not accurate in the first place or the fuel pump was marginal.

I've been studying up on Methanol and the boiling point of different fuels.
Gas has a boiling point range from 90 degrees to over 300 degrees because it's not a single fuel but a complex hydrocarbon mixture.

Methanol has a single boiling point of 150 degrees and Ethanol has a single boiling point of 173 degrees.
Some guys let the engine run stone cold all the time and alcohol fuels are not going to run good in that environment. Especially if it's N/A.
 
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