Carb Crud Origins?

[Dick Weiss]

I don't believe the carbs can be completely dried; I just turn off the petcock about a 1/4 to 1/2 mile before shutdown
and I never start the engine after a long 'sit'--6-months(?) or lately = 1-3/4 years w/o pre-oiling the engine w/the
starter; It took about 1-1/2 minutes for the mechanical pump getting enough fuel for a start, but the oil is primed
thru 1st! Yes, battery should have a good charge and use the starter w/15-20 second intervals including rests.
Having the Carrera engine in place, the electric pumps are shut off until pressure gauge reads (or light) goes off.

[Wil Mittelbach]

Should you always run the carbs out of gas if you know you won’t be driving the car for a month or two?

Absolutely! As such, I always run my 65C cab's Zenith carbs dry when knowing I'll not be driving the car for about a week or more. Accordingly, never had carb problems upon restart after carb refill via the under floor board elec priming pump.

Wil:
Do have the specific pump brand / specs and installation pictures?
ChuckJ

Chuck -
As requested, herewith primer pump particulars and installation photos:-
Pump: Airtex E8902 6v low pressure 2.5-4.5 psi 0.5 gpm primer pump with free-flow thru pump when off. Available via special order at AutoZone.
Operation: Via under dash push-button switch, held for about 10sec till dry carb bowls filled.
- Wil

[Dave Wildrick]

Running the carbs. dry for a two week layover is an overkill. You'll kill your starter.

I use my priming bulb to fill the carbs before operating the starter.

[Ned Gorski]

Run aviation Fuel .. you will never have a carburetor issue again.

Regards Ned
55 cab

[David Jones]

Ned, Avgas is not a good option for our cars. Lead contaminates the oil and can shorten bearing life plus avgas is designed for relatively low compression engines running constant rpm at altitude. It has some advantages but given the choice and the price disparity ($5 a gal on average) I would go with pump gas and keep my fuel system in good order. My carb problems are related to evaporated fuel in the main in summer time and probably leaks in the winter time and my own constant fiddling to get the perfect idle and pick up on acceleration.

[Ned Gorski]

David

i over winter with it .. i run it through all my toys and lawn equipment snow blower generators chainsaws weedwackers blowers and so on anything that sits more than runs.i have a lot of things with carburetors. i was constantly taking them apart cleaning and rebuilding before i started using av gas . i haven't had to rebuild a carb in 6 or 7 years.. This is the first i heard about the bearings, how does it affect the synthetic oils ? to be honest lately i been driving my cab less and less only a few 100 miles a year .. and the motor is quite tight oil looks like new every time i change it twice a year with synthetic .. because of the not driving a lot bearing contamination is a worry of mine.

Regards Ned

[David Jones]

Ned, synthetic oil and lead do not mix. Many years ago Shell sold synthetic oils for aviation use and very quickly found that although the engines ran better they failed faster. See the attached. I am big fan of synthetic oil but I would never run leaded fuel in anything but engines with valve seats that needed it which are usually old aircraft engines and old American V8's with unhardened valve seats. Running unleaded gas in these engines caused valve recession mostly of exhaust valves. You would notice this happening as you lost power as the valve clearance closed up and the engine ran quieter as the 4 exhaust valves ceased to tap on the rockers.
https://generalaviationnews.com/2005/04 ... mbination/
I am now running Shell Rotella "T" and on a 10K mile old engine the oil has just started to darken after 1000 miles. With having 4 cars to drive for pleasure like you I do not get to put the mileage on the cars they deserve so running synthetic was overkill.
By the way I never put any additives in my gasoline and this week will make it about 6 months since I filled my cars with gas not knowing I would spend most of Winter in ICU and then 3 months recuperating till I am this past week capable of driving the cars. No issues with starting or running so far.

[Martin Bruechle]

By the way I never put any additives in my gasoline and this week will make it about 6 months since I filled my cars with gas not knowing I would spend most of Winter in ICU and then 3 months recuperating till I am this past week capable of driving the cars. No issues with starting or running so far.

I never use Stabil either. Just took my boat out after buying 2 batteries and it ran great with gas from November.
Having had over 150 cars and a shop in the 80's used to flip them and may projects bought had 1 - 3 year old gas.
As long as it hasn't turned real bad with the strong varnish smell just run it or dilute it.
Nowadays with injection I don't think running old gas would be a good idea.

[Wil Mittelbach]

In regards to fuel storage and Stabil:-
Today's gasoline with a percentage of ethanol is hygroscopic, and will contribute to steel fuel tank ullage rust.
To preserve my 65C's still pristine original fuel tank, I attempt to maintain a resonably full tank to minimize ullage, and use Stabil with its additive for mitigating fuel tank ullage rust during longer periods of car non-usage.
Of note are the numerous past postings regarding fuel tank rust-thru, pinhole leaks, interior coating difficulties and tank replacements - some of which may have been avoidable.
- Wil

[Martin Benade]

Wil, when you use the word ullage do people know what you mean? Now that I looked it up I do, but never heard it before.

[Wil Mittelbach]

Wil, when you use the word ullage do people know what you mean? Now that I looked it up I do, but never heard it before.

As a clarification:-
Ullage definition: The volume by which a liquid container falls short of being full.
As used in my preceding post: The empty space/volume above the gasoline's surface in a 356 fuel tank subject to rust.
-Wil

[Ken Lubke]

I have 3 BP stores. Anything small engines, that are not used in a constant manor, will develope deposits with ethanol blended fuels . The higher the octane doesn't mean there is less ethanol in it. Non oxy premium is a non ethanol gas. Burns very clean and looks the same.. Those of you that have alot of little carbs should consider always using it. A little sea foam does help in cleaning. If my coupe sits for more than a week, I just prime carbs with a squeeze bulb or two of gas into bowls to help save starter.
IMHO

Kenny
65 outlaw

[Bruce Smith]

Just noticed this post, I've been away for a while. I wrote an article for the magazine a few years ago about the stuff that builds up in carbs & pumps and how to clean them. Here's a link for anyone interested:

http://www.sparkingplugs.com/resources/ ... gistry.pdf
http://www.sparkingplugs.com/3.html

Cheers,
Bruce

[Dave Wildrick]

Just noticed this post, I've been away for a while. I wrote an article for the magazine a few years ago about the stuff that builds up in carbs & pumps and how to clean them. Here's a link for anyone interested:

http://www.sparkingplugs.com/resources/ ... gistry.pdf
http://www.sparkingplugs.com/3.html

Cheers,
Bruce

Thanks, Bruce.
I probably saw article this but failed to appreciate it.

It effectively answers the question about where the stuff comes from in the carb bowls after gas sits there without the motor being run for months at a time.
Personal experience has shown me that Webers are especially prone to idle jet clogs from such crud.

Your article also explains why additives like Stabil won't resolve this dilemma and might actually make things worse.

So, if you know you won't be running the car for a matter of weeks, the best strategy is to run the carbs dry and keep your fuel tank as full as possible.