Go Back   The Ford Barn > General Discussion > Model A (1928-31)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 02-06-2019, 11:12 AM   #1
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Is fuel bubbling normal

I have a 31 Tudor. I notice that the fuel in the little plastic fuel filter I have on it seems to bubble as if boiling when I shut the engine off after driving. The carb is pretty warm but does not seem excessively so. Is this normal or does it indicate a problem?
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 11:30 AM   #2
chrs1961815
Senior Member
 
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 159
Default Re: Is fuel bubbling normal

I would say that it is probably boiling. I can't really think of any other reason why it would be. Do you use any additives in your fuel?
chrs1961815 is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 02-06-2019, 11:33 AM   #3
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

No additives. Should I be?
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 11:38 AM   #4
chrs1961815
Senior Member
 
Join Date: Jul 2018
Location: Spring Grove, Illinois
Posts: 159
Default Re: Is fuel bubbling normal

Quote:
Originally Posted by Rusty Karz View Post
No additives. Should I be?
No I was just thinking if it could be something chemical. Do you use regular gas?
chrs1961815 is offline   Reply With Quote
Old 02-06-2019, 01:01 PM   #5
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

I use regular gas.
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 01:07 PM   #6
1crosscut
Senior Member
 
1crosscut's Avatar
 
Join Date: Feb 2011
Location: Lincoln, Nebraska
Posts: 1,179
Default Re: Is fuel bubbling normal

Rusty if your gas tank doesn't have excessive rust/debris and you have a pencil filter in you don't need the plastic filter.
__________________
Dave

It'll feel better when it quits hurting.
1crosscut is offline   Reply With Quote
Old 02-06-2019, 01:12 PM   #7
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

Tank has been cleaned and treated. Not sure if I have a pencil filter. Don't recall seeing one.
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 01:16 PM   #8
Curtis in MA
Senior Member
 
Join Date: Oct 2017
Location: Leicester, MA
Posts: 142
Default Re: Is fuel bubbling normal

How long does it do it?
If you have a pin hole as it cools it might suck air in.
Curtis in MA is offline   Reply With Quote
Old 02-06-2019, 01:16 PM   #9
Bruce_MO
Senior Member
 
Join Date: May 2010
Posts: 278
Default Re: Is fuel bubbling normal

If the filter is a long way from the carb, I can't see how it's boiling. Even if it's close, I would guess it's simply air bubbles as the fuel drains a bit down to the carb as it's shut off. Check its temp with your hand or a cheap infrared temp indicator from Harbor Freight. They're super handy. I just googled boiling temp of gasoline and it's 203 degrees F.


I have clear fuel lines on a '53 Ford flathead and I see a surprising amount of bubbles. If you don't have symptoms of fuel starvation (sputtering and missing at high speed), I'd say you're fine. Good luck
Bruce_MO is offline   Reply With Quote
Old 02-06-2019, 01:17 PM   #10
Will N
Senior Member
 
Will N's Avatar
 
Join Date: Jul 2010
Location: New York
Posts: 656
Default Re: Is fuel bubbling normal

IMO, the sediment bowl that is already in the system is enough to deal with what you'll experience with a clean and sealed tank. Adding an inline filter will just impede fuel flow in a gravity fed system.
Will N is offline   Reply With Quote
Old 02-06-2019, 01:17 PM   #11
eagle
Senior Member
 
eagle's Avatar
 
Join Date: Aug 2011
Location: Eagle Bend, MN
Posts: 1,368
Default Re: Is fuel bubbling normal

If you are getting excessive heat, yes gas will boil at somewhere around 200+ degrees F, depends on the blend. If the timing is incorrect, then there will be excessive heat. If all is running fine, just some boiling in the line at shutoff, it won't hurt anything. If its really a hot day 200 degree engine bay in ok.
__________________
"There are some that can destroy an anvil with a teaspoon and shouldn't be allowed to touch anything resembling a tool."
eagle is offline   Reply With Quote
Old 02-06-2019, 01:24 PM   #12
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

It stops when I shut the tank valve off. Sorry I did not think about it until just now
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 01:29 PM   #13
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

Thermometer would be handy. Getting one next time.
Rusty Karz is offline   Reply With Quote
Old 02-06-2019, 02:12 PM   #14
midgetracer
Senior Member
 
midgetracer's Avatar
 
Join Date: May 2010
Location: Bismarck ND
Posts: 836
Default Re: Is fuel bubbling normal

The initial BP of gasoline is about 95 degrees F. it is a mixture and the final BP is about 200F
midgetracer is offline   Reply With Quote
Old 02-06-2019, 06:31 PM   #15
Fhane
Junior Member
 
Join Date: May 2010
Location: Stuart Florida
Posts: 19
Default Re: Is fuel bubbling normal

Plastic fuel filter. Sounds like a fire hazard to me. Should be a steel fuel line. No rubber no plastic.
Fhane is offline   Reply With Quote
Old 02-06-2019, 08:29 PM   #16
Kurt in NJ
Senior Member
 
Kurt in NJ's Avatar
 
Join Date: May 2010
Location: on the Littlefield
Posts: 4,496
Default Re: Is fuel bubbling normal

If you use the cast iron sediment bowl, and steel pipes you never have worries about fuel bubbling
Kurt in NJ is offline   Reply With Quote
Old 02-07-2019, 08:15 AM   #17
HD Rider
Junior Member
 
Join Date: Oct 2018
Location: Glendive MT
Posts: 19
Default Re: Is fuel bubbling normal

If you are using an ethanol blend, ethanol has a much lower boiling point. Something like 147*.
HD Rider is offline   Reply With Quote
Old 02-07-2019, 08:24 AM   #18
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

Only fuel available here is 10% ethanol.
Rusty Karz is offline   Reply With Quote
Old 02-07-2019, 08:26 AM   #19
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

Plastic filter is far from the manifolds but I'm probably going to get rid of it as I'm sure it is a weak link in the system.
Rusty Karz is offline   Reply With Quote
Old 02-07-2019, 08:30 AM   #20
Rusty Karz
Member
 
Join Date: May 2011
Location: Dallas, TX
Posts: 35
Default Re: Is fuel bubbling normal

Thanks to all who replied. weather has turned bad here so I won't be taking it out for a while but I did buy the infrared thermometer and that should tell the tale if the engine is over heating. This car is an ongoing project and I'm glad you guys are here to ask for help.
Rusty Karz is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 12:40 PM.