Carb tuning for ethanol in gas.

ac auto

ac auto

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Joined
Jan 10, 2017
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Location
West Newfield, Maine
I just started working on my 93 Vmax 750 and have the carbs off to clean. Should I make any changes to adjust for the new crappy gas? What should I set the fuel screws at? Thanks. 94 vmax 750.jpg
 
Sorry, the ethanol is added to the gas here. Up to 10% We have no choice but to use it. Was advised to go an extra 1/4 to 1/2 turn out on the fuel screw for my Viper.
 
What jets are in it now?
Are your float blow vent tubes vented to the air box or stock?

Dont turn anything. Cant think of any fuel screws, so what did you want to turn?
 
leave your carbs alone and go to your local auto parts store or lawn garden and add a ethanol fighter made by sta-bil or lucas. now i don,t believe ethnol has any affect on jetting, what it dose affect is the o-rings in your carbs. 3:16x (yammie tony)
 
I run 93 ethanol for years in my 93. I have newer o-rings and check and clean carbs every year though. I run 50 pilots but my sled is piped. It actually ran fine with the 47.5 but I like the safety margin for real
Cold days. Screws are at 1-3/4 I believe.
 
Mark, ethanol is an oxygenate. Ethanol is why you moved the needles on your Viper. If jetting is left untouched, switching from non-ethanol fuel to ethanol fuel will result in a leaner burn. If the Vmax4's are on the rich side from the factory through the low speed and midrange, then you are probably ok. Vipers were lean (for fuel mileage) and the timing is more aggressive (than SRX's) in the mid-range that is why it is more critical on the Viper. Additives do not eliminate the oxygenating properties of the ethanol fuel. They only help prevent the ethanol fuel from breaking down so quickly and forming the dreaded gell. The ethanol also acts as a very powerful detergent, so I will clean any dirt/debris from the system. The ethanol also can damage and breakdown any rubber in the fuel system. I haven't had a problem with it aside from the gell when I left it in the carbs too long without a stabilizer. Also remember, in New England, ethanol replaced MTBE when they banned that so it's been around for many years. Not really a "new" problem.
 
I've been using Startron in my 2 stroke motorcycles, lawnmower, weedeater, etc. It's easy to find and relatively cheap. I dose each tank of gas.

http://www.starbrite.com/startron

My daughter stored her car for 2 years. I treated the gas with Startron before it was stored, and it started right up and ran fine two years later.
 
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