How to Prevent Holley Carburetor Fuel Boiling

-
BSB67 said:
Seems a bit strange that you didn’t have problems all summer before now. Was it hotter than usual?

Possible that you got a batch of winter fuel with a higher RVP? I believe the switch date is September 15. This has happened to me on hot days near the 6/1 and 9/15 transition dates having the high RVP fuel on hot days with a long engine run.

Knowing this, I work around it.
Click to expand...


I’m not sure we switch to winter blend this early. The OP is fairly close to where I live.

I could be wrong though but I don’t think that happens until mid October.

It is strange this just started though.
 
Bonkled_2900 said:
First time this happened, drove all summer and we had just filled the gas the day before
Click to expand...
Did you fill with E10? (And may be not know it) I have had that issue in the heat of summer and non ethanol unleaded sure does help. A cooler running engine may help as well. An insulator under your carb may help. A return fuel system may help. An electric fuel pump with a momentary switch may help those restarts. Are you seeing a trend here? All the things I mentioned may help but no one thing is a guarantee to cure the issue. The electric pump will help the "empty carb due to evaporation" issues and the return fuel system will help with the "vapor lock while running" issue if that's what you are experiencing. Gee, may be an electric pump with a return fuel regulator would cure both issues. :thumbsup:
 
Summer to Winter switch is September 15 in Idaho, according to the Google Man. Could be dated info, or different if you’re in an ozone non-attainment area.

Also, if the problem is engine-off heat soak, not sure the return fuel line will help. Opening the hood would solve the problem, but might not always be practical.

I have two vehicles with different fuel/temp issues with winter gas on hot days. One is vapor lock, the other is fuel boiling in the carb while driving. Knowing the specific condition and cause Ihave been able to easily work around the conditions.
 
BSB67 said:
Summer to Winter switch is September 15 in Idaho, according to the Google Man. Could be dated info, or different if you’re in an ozone non-attainment area.

Also, if the problem is engine-off heat soak, not sure the return fuel line will help. Opening the hood would solve the problem, but might not always be practical.

I have two vehicles with different fuel/temp issues with winter gas on hot days. One is vapor lock, the other is fuel boiling in the carb while driving. Knowing the specific condition and cause Ihave been able to easily work around the conditions.
Click to expand...


And I just checked it’s 9/15 here too.

Luckily I’ve been keeping notes of specific gravity of different pump fuels but I don’t think I’ve checked winter blend yet.

That’s if the specific gravity changes with the different blends. It may not.
 
Newbomb Turk said:
I’m not sure we switch to winter blend this early. The OP is fairly close to where I live.

I could be wrong though but I don’t think that happens until mid October.

It is strange this just started though.
Click to expand...
I don't know about winter blend..... but I saw Christmas trees on display at Costco on the last day of August. Wtf?
 
MOPAROFFICIAL said:
I've never had fuel boiling in any carburetor.
Click to expand...
I have and I've documented it. To be more accurate, it was the light end of the fuel mixture evaporating - not boiling like water or coolant does. When the light components vaporize in the bowl the boosters can be wet but the main characteristic is removing the air cleaner top makes it it go super lean. My point is shouldn't be seeing large amounts of liquid fuel coming out hte boosters due to hot fuel in the bowls. Much of the vapor goes out the bowl vents.

Bonkled_2900 said:
leaking from the boosters and flooding the engine
Click to expand...
It may be vapor related but if so I suspects its vapor in the fuel line that pushed liquid fuel into bowl.
Chrysler had 3 fixes once the culprit had been narrowed down.
1. Tilt the fuel filter so the vapor goes out the outlet rather than push fuel (c. 1963). Later of course there were vapor recover lines
2. A small internal bleed in the fuel pump (circa 1972-3)
3 An earlier (1960s) kit that did the same to address hot restart problems.
4. if really desprate, techs were advised to relocate the fuel filter before the pump for certain heat issues (knowing this is a compromise)

BSB67 said:
Is this the first time you had this problem? Have you been driving it all summer and this was the first event like this?
Click to expand...
Great point!
Bonkled_2900 said:
First time this happened, drove all summer and we had just filled the gas the day be
Click to expand...

BSB67 said:
Summer to Winter switch is September 15 in Idaho, according to the Google Man. Could be dated info, or different if you’re in an ozone non-attainment area.
Click to expand...

This certainly is a possible culprit. There is a date for the refiners to switch over to the winter stuff and another date for when it must be in the retail station's tanks. Winter fuel is cheaper to produce so there is an incentive...

Here's where I posted about the Chrysler kit while working on insulating the line from my self inflicted winter fuel issues
www.tapatalk.com

racingfuelsystems-What to do about Winter Fuel in hot temperatures?

Not sure where to post this, but the carb is a Holley and the problem was it wouldn't take a load at interstate speeds when the air temperatures were
www.tapatalk.com www.tapatalk.com
 
Last edited:
You must log in or register to reply here.
-

Back
Top