Ethanol and Webers

[Quickstep192]

I was describing my 2800 rpm popping problem to someone over the weekend and he suggested that it could be tied to the older parts in my Webers not dealing well with ethanol gas. That makes sense to me since it seems like my problem arose around the time that I became unable to get 94 octane non-ethanol gas. I'm curious for any thoughts on this. The only thing I could think of was the accelerator pump diaphragms and I'm pretty sure the accelerator pumps aren't my problem. Any thoughts on other parts in the carbs that might not like dealing with ethanol gas?

[Jack Stands]

How often do you drive your car? The ethanol laced fuel does turn into a jelly like substance if it sits too long, and also can phase separate. In addition, the ethanol acts as a solvent that dissolves other sediments that may have accumulated in the fuel system over the years, and plugs up the fuel filter. It's a real problem in the pleasure boating, RV, snowmobile, and other seasonal gasoline engined items. If you keep driving and using up the fuel, it would be better once any sediments are cleared.

[Jack Stands]

Also, check your jets as that is just about the rpm range where you're transitioning from the idle to the main jets. Having access to an exhaust gas analyzer would be helpful, but popping through the carbs is usually signaling a lean condition being present.

[1QuickS]

Jetting is typically richened for use with ethanol, sounds like your transition is lean and a larger idle jet will probably set things straight. You can perform a little test to see if that is true by opening up the idle mixture screws one full turn and see if the issue goes away. If you do install new idle jets then you will need to re-adjust idle mixtures for "Lean Best". Check out my web site for "Lean Best" adjustment procedure to help with this:

Performance Oriented

The main circuit can also be adjusted to help the transition lean issue but it is much easier to increase idle jet size.

Use some Marine Grade Stabil fuel additive to help tame the aging of ethanol.

[zedsn]

I had ethenol break down in my weber carbs and it actually started to eat the pot metal. It turned into a white paste and I couldn't believe my eyes. I do not know how long the fuel was sitting in there but I doubt too terribly long. I had bought the car as a project and was having carb issues so I took the tops off and saw what was inside of the float bowl areas.

[Jack Stands]

That's the same stuff I found in mine when the car sat for over a year (I couldn't drive it because of knee replacement surgery), but Paul Abbot at Performance Oriented did a great job of rebuilding the Webers, and now it runs great.

BTW, I had my left knee replaced first so I could work the clutch before our driving season was over. If you have bad knees, don't hold off too long like I did. Life's too short to not be driving your Porsche!

[1QuickS]

My understanding about the white goo is that the ethanol reacts with the fiberglass resin used in the holding tanks at the gas station. AND, if you have had your fuel tank cleaned and sealed then there is the real chance that the sealant is not ethanol rated and will cause the goo to appear.

Throttle bodies for Webers, Solexes and Zeniths are all made from die cast aluminum, not pot metal. There are some components that are of die cast zinc, for the Weber they are:

• auxiliary venturis
• accelerator pump bodies
• accelerator pump top covers
• accelerator squirter nozzles

[zedsn]

My gas tank is steel and is clean inside. I removed all of it from the tank after I saw the white paste in the carbs. The float bodies of the carbs looked like pot metal to me but I could be wrong.

[Quickstep192]

I've drained some gas from the carbs (downstream from the filter) and I'm seeing gas, not goo, but I'd be willing to bet that the gas is octane depleted from sitting.