Fuel evaporation thread over on the Camaro forum

[VintageMusclecar]

I've often been asked about carbs with mysterious drainage/leak issues as evidenced by the need to crank the engine excessively after the car has sat for a week or so. General consensus seemed to indicate the carbs are leaking fuel internally (particularly in the case of QJets).

I've been meaning to perform a test like this for a while now but for a variety of reasons I've not gotten around to doing it...turns out someone beat me to it, and they posted the results over on the Camaro forums.

Click here

This should help put a lot of old wife's tales to rest.

[VintageMusclecar]

FWIW, despite the OP stating the discoloration appeared to be more of a lighting issue to them, I have noticed a considerable change in fuel color (and aroma) in a matter of days in the fuel cell on my test engine.

[WILMASBOYL78]

As you all know the current ethanol based fuel is junk [img]<<GRAEMLIN_URL>>/thumbsdown.gif[/img]

We have switched to using Av-Gas in all of our equipment and toys including lawn mowers, chainsaws, outboards, weed trimmer, snowmobiles, ATV, etc...no more carb problems...the Av-Gas lasts a long time with no discoloration or foul smell [img]<<GRAEMLIN_URL>>/biggthumpup.gif[/img]

We also use it in the high compression cars and often blend in a little race fuel to make it perfect. Some of the gas stations in the upstate area of NY are now selling ethanol free high test...the snowmobile crowd is very grateful [img]<<GRAEMLIN_URL>>/beers.gif[/img]

Wilma

***what can you do with old gas?? can it be recycled??

[Salvatore]

yes, Tommy the gas thing is an issue. I mix 112 Sunoco with 93 octane. cars run good and no problems all year long. My Q-Jet nova does need to crank way more times than the Holley on my Z/28. The 2 bottom plugs on the body have been epoxied over but still it seems to need to crank longer. I usually run 3+ gallons of 112 to about 10 gallons of 93.

[ktownkid]

I don't know anything about the evap. subject...but all items Tom mentioned...I had to have repaired, due to gummed up carbs and fuel systems. Now, I keep gas 30 days max...

If you don't stay on top of it...you will regret it...

ktownkid [img]<<GRAEMLIN_URL>>/youguysrock.gif[/img]

[WILMASBOYL78]

The ethanol fuel works ok in our daily drivers because the gas is &quot;used up&quot; quickly...the longer this stuff sits, the worse it gets. Star-Tron is a good additive if you are stuck with ethanol.

wilma

[Mr.Nickey Nova]

Have the same problem with the Q-Jet on my L34 Nova.It's hard to start when sitting for three or more days.Have to crank the engine to reprime the carb and with a few pumps she fires right up.Now my 69 Z with the Holley can sit for a few weeks and with a few pumps fires up with no problem.. Maybe it has something to do with the size of the float bowl area,like do the Holley carbs hold more fuel than a Q-Jet???