Fuel pump and ethanol?

Vettenick

Vettenick
Jul 17, 2019
418
The newer pump materials are supposed to be ethanol resistant, but if this thing has been sitting a long time, I would swap it out. Considering if the diaphragm leaks, it could go into the oil pan, get you stuck, or worse....a fire.
 

bfendick

Veteran Member
Dec 3, 2006
153
Vernon, BC
The addition of the ethanol to the gas is hard on all older vehicles as the ethanol dries out the rubber hoses, seals and gaskets in the fuel system including messing with the fuel tank sending unit. I always buy non-ethanol fuel and use Chevron 94 octane exclusively and tuned the engine for it.
 

hubedobeedo

3rd times a charm
Jul 18, 2013
999
Huntertown,IN
The addition of the ethanol to the gas is hard on all older vehicles as the ethanol dries out the rubber hoses, seals and gaskets in the fuel system including messing with the fuel tank sending unit. I always buy non-ethanol fuel and use Chevron 94 octane exclusively and tuned the engine for it.
it is bad to leave sit in aluminum carbs too. if it is anodized might help most are not. if you have drove since must be ok for now. at least you're driving it!
 

TTR230

Veteran Member
Aug 1, 2020
669
Burlington, Ontario
it is bad to leave sit in aluminum carbs too. if it is anodized might help most are not. if you have drove since must be ok for now. at least you're driving it!
I have found the ethanol gas leaves a much bigger mess behind if left to evaporate from a small vessel like a float bowl. I will say though, that it doesn't seem to turn to that vile smelling varnish as quickly as gas used to.

Fun fact: I just bought a vintage race bike that I can verify had been sitting for about 15 years with a tank full of cam 2 purple race gas, and it still looks and smells as if it was just pumped. I don't know if the premix helped. I may put it in the lawnmower for scientific purposes.
 

sandlapper

Veteran Member
Oct 9, 2020
1,629
SE CSA
I bought a vintage vette some years back, PO drove it only couple times a year but then only for a few miles. It had classic symptoms of gummed up system. Sooo, before I headed out for the +700 mile return trip --- I chatted up the local circletrack's fuel concession and got a full tank of fresh race fuel. Smelled heavenly, and within 20-30 miles it cleared any schmutz --- including dissolution of the fuel sock! Only thing left was its grommet. Easy viewing / replacement thru very large filler on deck lid. All good. I've done similar w/ LL100 but it's never melted a sock. Nowadays, Local FBOs can't be depended upon to permit direct-filling non-aircraft --- unless well acquainted.
 

FS87LT

Veteran Member
Apr 3, 2010
102
DFW, TX
Back to the original post . . . considering the price of an OEM-style fuel pump for that motor, consider it "cheap insurance" to go ahead and change it out and be done with it.

In another forum a few years ago, it was mentioned that a fuel pump rebuilder in the northeast would rebuild vintage fuel pumps using the ethanol-resistant diaphram for a bit over $100.00 (at that time). Last time I checked on a new fuel pump for my '77 Type LT 305 (same pump part number as the Gen I 302, two line pump), it was like $30.00 USD. THAT's cheap insurance to me.

Ethanol dries out rubber fuel lines from the inside out. Akk fuel lines built since about 1990 are supposed to be ethanol resistant. Allegedly fuel pump diaphrams which have been allowed to dry out, even with the ethanol resistant rubber in them, CAN get brittle and fail.

Enjoy!
FS87LT
 

67johnny

Veteran Member
Apr 14, 2016
438
vancouver
I have had more problems with the Holley carbs than the Edelbrocks but the Aluminum bodies do not fair well when using regular fuel with 15% ethanol in play.
That said... the issue is so bad with Lawnmowers and chain saws that most manufacturers now mandate Premium fuel and its not due to high compression mandating higher octane fuel.
Here is an interesting read on the subject.> https://www.onallcylinders.com/2014...derstanding-ethanol-can-protect-classic-ride/
 




Latest posts

Top