LanEvo Reader
11/16/16 6:49 p.m.

We've just completed the carb conversion on my 190E 2.3-16 vintage racer. I'm so happy to get out of Bosch KJet/CIS hell and into the world of dual Weber DCOE's.

One question remains. Do I have to worry about all the ethanol in modern fuel?

Is there an additive I should be using? I've heard old-timers talk about adding some Marvel Mystery Oil, Lucas Upper Cylinder Lube, and even diesel fuel (or kerosene) to the tank. The BMW guys seem to like Chevron Techron. And someone was telling me about Driven Carb Defender.

What do you think?

VClassics Reader
11/17/16 11:36 a.m.

Ethanol will rot old fuel hoses, but other than that I've seen zero problems.

LanEvo Reader
11/17/16 12:48 p.m.

In reply to VClassics:

The whole fuel system (pump, lines, fittings, etc.) is all brand new.

I was more worried about the carb itself, like the float needles.

11/17/16 1:46 p.m.

Seems like one more reason to run Chevron Supreme then. Always my top fuel choice.

VClassics Reader
11/17/16 3:36 p.m.

Nope, no problems with Webers that could be attributable to ethanol going back 20 years or more. It doesn't seem to bother brass or plastic floats at all.

BrokenYugo UltimaDork
11/17/16 3:51 p.m.

Double dose marine stabil if it's gonna sit. I like to shoot some 2 stroke oil down the bowl vent if it's gonna sit for months (keeps any varnish gummy and easily dissolved by fresh fuel), nothing other than that. A lot of "ethanol gas problems" are really just modern twice as volatile as it was in the 70s gas problems, today's ethanol free is just as likely to give vapor lock issues or turn to varnish in 6 months as run of the mill E10.

jharry3 GRM+ Memberand New Reader
11/23/16 5:24 p.m.

Ethanol attracts water. If you are going to sit up for a while you may want to drain the bowls in the carbs in addition to the Stabil in the tank. My lawn mower sucked up a bunch of atmospheric water in its fuel tank and I had to drain it and flush the carb as well. That was with standard E10.

frenchyd Reader
1/3/17 2:36 a.m.

In reply to LanEvo: Grassroots did some testing of ethanol fuels. Bottom line? There is some added power there and not much problem. Want cheap power gains? Consider rejetting for E85*.

Careful though with alcohol. First there are two kinds. Ethanol and methanol.. Ethanol is not the demon some think. We can drink ethanol ( only if it's pure in-denatured stuff. The 2% poison they add to makes it undrinkable).

Methanol is nasty stuff. You don't want to breath it or have it touch you anyplace. Plus it will attack aluminum etc so you have to drain and flush it. Don't leave it in the carbs or fuel tank!!! Methanol will make the most power though..

  • E85 bought at a gas station may have anywhere from 33% ethanol to 85% ethanol.. plus the base stock of the gasoline it's mixed with can be pretty crappy. On top of that it may have been sitting in the underground tank for a long time absorbing plenty of moisture. E85 bought from a race gas supplier tends to be very high grade of stuff.. but still should not be left in for a long time..
Jerry From LA
Jerry From LA SuperDork
1/19/17 5:22 p.m.

In reply to frenchyd: The "poison" in de-natured alcohol is methanol.

frenchyd Reader
2/7/17 1:57 a.m.

In reply to Jerry From LA: Yes it can be methanol, or it can be gas. Anything that will blend completely and still make ethanol undrinkable is used. Given the low cost of methanol it probably is when high volume is involved.

When I was sprint car racing and had access to pure ethanol I used 2% Nitromethane and jetted accordingly. I covered the smell with Caster oil.

tr8todd Dork
2/7/17 6:53 p.m.

I use to squirt in a little Marvels when the temps were below 55 or so. Seemed to help with all the popping and spitting they tend to do when they aren't adjusted just right. You will find that a setting that works when its 80 won't work as well at 55*. Gets to be a pain if you have an early session here in the Northeast and its still cold, but later in the day the race sees warmer temps. A little squirt and you can still run the race setup and won't screw yourself trying to find the magic mixture.

LanEvo Reader
2/20/17 2:06 p.m.

When you say "squirt in a little MMO" do you mean add some to the tank?

Our Preferred Partners