Fuel boiling in carb - JeepForum.com

Reply
 
LinkBack Thread Tools
post #1 of 45 Old 06-11-2013, 08:38 PM Thread Starter
jbrown73
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2013
Location: West Columbia
Posts: 140
Fuel boiling in carb

Okay, drove the rig today for about 45 minutes in 90 degree heat and when I got home and pulled in the garage I noticed an odd noise coming from under the hood. Checked it out and heard a boiling sound coming from the carb bowl. The fuel hose and carb-mounted air filter were hot to the touch.....even the hood support rod was hot. Rechecked the temp gauge and it is reading correct at 185 Fan is rotating normal and moving plenty of air.

Does anyone have any insight into this? Is this normal for my set up?

258I6, Weber 32/36, Nuttered, Team Rush, new radiator, thermostat, fan clutch, belt, alternator, starter, fuel pump, head gasket, exhaust/intake manifold gasket, harmonic balancer, water pump, idler pulley, a/c components removed, ignition coil, etc, etc, etc.

jbrown73 is offline  
Sponsored Links
Advertisement
 
post #2 of 45 Old 06-12-2013, 05:47 AM
vadslram
Registered User
1990 YJ Wrangler 
 
Join Date: Jan 2006
Location: VA Beach
Posts: 6,235
Garage
That sounds a little unusual...and dangerous. boiled gas vapors are explosive.
Any idea where the extra heat is coming from? There should be plenty of open spaces under and around the engine that the ~185 degree air coming through the radiator can also at least slightly cool the engine compartment.
I know in my previous detroit iron big 8 days insulating the headers brought the temps down and louvering does a lot. but since most jeeps don't have this issue I'm thinking you have a problem somewhere.
If the engine compartment is reasonable hot but the carb boils try to get a spacer. A small chunk of plastic/fiberglass that will insulate the carb from the intake.
vadslram is online now  
post #3 of 45 Old 06-12-2013, 07:09 AM
superj
Registered User
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
mine used to do that but i think it was a timing deal. i cannot remember because it was a long time ago but it was on the weber 34 i had. i think its from the exhaust being right under the intake, like there should be a shield in there but its not there

I don't feel like working on anything at this time so i sold my yj.
superj is offline  
post #4 of 45 Old 06-12-2013, 07:18 AM Thread Starter
jbrown73
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2013
Location: West Columbia
Posts: 140
Yeah, dangerous was the word that came to my mind as well. And considering this will be my son's rig in the near future, I want to get this resolved asap. Even the wife made a comment when she got home and pulled in the garage that it smelled like gas.....went ahead and opened both garage doors at that point for ventilation.

There is plenty of room under the hood and the Weber has 2 spacer plates that it is mounted on top of....will take a pic when I get home from work and post to the thread. When you say 'louvering', what exactly are you referring to? Louvers on the hood to let the heat escape up through the hood?

The only sources of heat are the normal ones under all Jeep hoods (manifolds, radiators, etc). I have not installed headers or any aftermarket engine components other than the Weber. The fuel lines (source & return) are routed over top of the valve cover with the inlet port on the valve cover side (will see what I mean when I post the pics).
jbrown73 is offline  
post #5 of 45 Old 06-12-2013, 07:32 AM
vadslram
Registered User
1990 YJ Wrangler 
 
Join Date: Jan 2006
Location: VA Beach
Posts: 6,235
Garage
Louvering is an old hotrodder trick.


How is the rig running? SuperJ has a point. If your ignition or valve timing is off you might be blowing raw flames into the exhaust manifold and getting it red hot...that would add some heat under the hood.
vadslram is online now  
post #6 of 45 Old 06-12-2013, 08:55 AM
blown50
Registered User
1987 YJ Wrangler 
 
Join Date: Apr 2007
Location: MS
Posts: 134
I have to remove my water heating from my manifold in the summer, or it will do the same thing! I just bypass the manifold and let it run thru the heater core. I do have to hook it back up in the winter time though r it runs like crap
blown50 is offline  
post #7 of 45 Old 06-12-2013, 09:17 AM
zeus87gn
Automotive Neurosurgeon
 
zeus87gn's Avatar
1987 YJ Wrangler 
 
Join Date: Sep 2006
Location: Hernando, Ms
Posts: 2,447
Quote:
Originally Posted by blown50 View Post
I have to remove my water heating from my manifold in the summer, or it will do the same thing! I just bypass the manifold and let it run thru the heater core. I do have to hook it back up in the winter time though r it runs like crap
^^This^^

I had the same problem when I lived in Ga
Only I never routed it back thru the manifold
It ran lousy in the winter until it was fully warmed up

Handicapped license plates are not for mentally handicapped people -

"Man has not yet evolved an inch from the primordial slime that spawned him." Mark Blankfield, Jekyll & Hyde... Together again

Holley Carb thread
zeus87gn is offline  
post #8 of 45 Old 06-12-2013, 09:25 AM
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,145
Have you checked your timing chain? If you have a bunch of slack, your valve timing is way retarded and wil make your exhaust manifold hotter than normal.

Also,did you verify TDC on #1 when you installed your new V-damper?

418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline  
post #9 of 45 Old 06-12-2013, 11:35 AM Thread Starter
jbrown73
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2013
Location: West Columbia
Posts: 140
I have not checked the timing chain yet. I suppose I should have checked that out when I had all the components out replacing the harmonic balancer. The timing is currently set at 9 degrees BTDC @ 800 rpm and does not fluctuate at idle. That brings up another question for me......my service manual says to set the timing @ ~1500 rpm. If I set the timing to 9 degrees @ 1500 rpm, then the Jeep runs like ***** at idle and dies. A quick check of the timing at idle with it set like that says ~0 degrees.

Unless someone else has some sound mechanical advice here, I am stuck with tearing all those components back out just to check the timing chain.......jeez, I am almost ready to throw a 'For Sale' sign on this thing.
jbrown73 is offline  
post #10 of 45 Old 06-12-2013, 11:49 AM
superj
Registered User
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
you can check without a tear down

I don't feel like working on anything at this time so i sold my yj.
superj is offline  
post #11 of 45 Old 06-12-2013, 12:09 PM
dancytron
Registered User
1990 YJ Wrangler 
 
Join Date: Jun 2008
Location: st. louis
Posts: 1,936
Quote:
Originally Posted by jbrown73 View Post
I have not checked the timing chain yet. I suppose I should have checked that out when I had all the components out replacing the harmonic balancer. The timing is currently set at 9 degrees BTDC @ 800 rpm and does not fluctuate at idle. That brings up another question for me......my service manual says to set the timing @ ~1500 rpm. If I set the timing to 9 degrees @ 1500 rpm, then the Jeep runs like ***** at idle and dies. A quick check of the timing at idle with it set like that says ~0 degrees.

Unless someone else has some sound mechanical advice here, I am stuck with tearing all those components back out just to check the timing chain.......jeez, I am almost ready to throw a 'For Sale' sign on this thing.
The 1500 rpm thing is to deal with the computer advancing the timing on its own. Since you've nuttered it, the computer isn't in the equation anymore, so set the timing at idle (like a pre-computer motor).
dancytron is offline  
post #12 of 45 Old 06-12-2013, 02:31 PM
Old4X
Registered User
1990 CJ7 
 
Join Date: Nov 2008
Location: Ga
Posts: 5,145
Quote:
Originally Posted by superj View Post
you can check without a tear down
This

418 miles on 19 gallons of gas. Can't beat the BBD !
Old4X is offline  
post #13 of 45 Old 06-12-2013, 04:23 PM Thread Starter
jbrown73
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2013
Location: West Columbia
Posts: 140
Please elaborate. So I will not need to pull the fan & shroud, water pump, alternator & mounting brackets? My service manual says to take all of those components out to take the timing chain cover off.
jbrown73 is offline  
post #14 of 45 Old 06-12-2013, 05:23 PM
superj
Registered User
 
Join Date: Mar 2008
Location: corpus christi
Posts: 7,057
What I read is:

Pop top on distributor
Turn crank with wrench till timing mark is at 0
Then turn crank back and see how many degrees mark moves till distributor rotor moves
If more then 10 degrees, chain needs replacing.


Hopefully, I wrote the instructions properly

I don't feel like working on anything at this time so i sold my yj.
superj is offline  
post #15 of 45 Old 06-12-2013, 07:08 PM Thread Starter
jbrown73
Registered User
1989 YJ Wrangler 
 
Join Date: Jan 2013
Location: West Columbia
Posts: 140
Ahhhhh, now we are on the same page.....or at least I'm on the same page as the rest of you! I'll check that out tomorrow & post what I find.

By the way, thanks to all those who offer suggestions, solutions, and best practices for those of us who are new to the Jeep world.
jbrown73 is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Posting Rules  
You may post new threads
You may 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
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome