[DeTomaso] NPC-Carb boiling fuel?

Donny Williams donnylee at ccwebster.net
Sun Mar 18 12:31:55 EDT 2007


Tom-

I do not think this is going to take much to correct.  Pull the needle and 
seat and examine it carefully for any garbage.  The tiniest amount of crud 
can cause the problem.  The seat can be pulled from the top without tearing 
off the bowl from the carburator.  (Remove the top Lock Screw, and thread 
out the seat)

  Secondly, the fuel pressure should not be more then 9lbs.    I would 
suggest around 6lbs on a a street car. Regulators are adjustable. Thirdly, 
the float level is very important!  It should be just at roughly half height 
of the site window regardless of the float type. Or just start to weep over 
with the side brass plug removed.  Depending on which type of sights he has 
on the carburator.

This said, what may be occurring is gas does expand with heat.  If his float 
is adjusted to high this problem will happen.  Most notably at shut off when 
the fuel is warm.   If its happenning intermitant when its running my bet is 
simply to much fuel pressure and he is occassionally blowing off the needle 
with to much fuel pressure or you will find that tiny piece of garbage 
hanging out in the needle/seat.

All this said, it is simply one or more of these things and thats it.   Keep 
it simple, because it will be simple.

Donny





----- Original Message ----- 
From: "Tom Di Iulio" <diiulio at ix.netcom.com>
To: "'Art Stephens'" <artstephens at charter.net>; "'ROBERT SIMPSON'" 
<r.simpson35 at verizon.net>; "'Pantera Group'" <detomaso at realbig.com>
Sent: Saturday, March 17, 2007 9:30 PM
Subject: Re: [DeTomaso] NPC-Carb boiling fuel?


> Regulator is in place but I'm wondering about fluctuations. Will take a
> closer look tomorrow, thanks!
>
> -----Original Message-----
> From: detomaso-bounces at realbig.com [mailto:detomaso-bounces at realbig.com]
> On Behalf Of Art Stephens
> Sent: Saturday, March 17, 2007 4:59 PM
> To: ROBERT SIMPSON; Pantera Group; Tom Di Iulio
> Subject: Re: [DeTomaso] NPC-Carb boiling fuel?
>
>     If fuel pressure is too high,  maybe he needs a fuel pressure
> regulator?
>
> Art
>
>
> ----- Original Message ----- 
> From: "ROBERT SIMPSON" <r.simpson35 at verizon.net>
> To: "Pantera Group" <detomaso at realbig.com>; "Tom Di Iulio"
> <diiulio at ix.netcom.com>
> Sent: Saturday, March 17, 2007 5:01 PM
> Subject: Re: [DeTomaso] NPC-Carb boiling fuel?
>
>
>>I posted your question on a Camaro Club Forum I am a member of, hope
> this
>> helps.
>>
>> Post 1.  Somehow too much fuel is getting in - too much fuel pressure
>> (something below 8psi is ok on a Holley), the float is set too high or
> has
>> sunk, or something has jammed the needle valve open.
>>
>> I'd suggest pulling the front fuel bowl and 'rebuilding' it, if the
> carb
>> otherwise seems ok. Dip the fuel bowl in carb cleaner for a couple
> hours,
>> get a new gasket set for it, change the needle/seat. If the float is
>> brass,
>> if there's no fuel inside and no obvious damage or holes, its probably
> ok
>> to
>> reuse. If its a plastic float, replace it. They are somewhat known to
>> absorb
>> fuel over time.
>>
>> Post 2. The float needle is the only way gas can get into the bowl.
>> Therefore it is either dirt or bad float needle assembly or fuel
> pressure
>> is
>> too high. Would be odd if it's fuel pressure as it would always be an
>> issue
>> hot or cold, assuming constant fuel pressure of course.
>>
>> Good luck
>>
>> Bob
>> #3468
>> ----- Original Message ----- 
>> From: "Tom Di Iulio" <diiulio at ix.netcom.com>
>> To: "Pantera" <detomaso at realbig.com>
>> Sent: Saturday, March 17, 2007 12:20 PM
>> Subject: [DeTomaso] NPC-Carb boiling fuel?
>>
>>
>>> Hi all,
>>> I have a friend with a 69 chevelle, 350 with holley (new) 650 dbl
>>> pumper, mechanical secondaries. After the car has warmed up, the carb
>>> will frequently barf up fuel thru the front air horn. This does not
>>> happen with the back bowl. The carb bowls are not so hot that you
> can't
>>> touch them, they're relatively cool at the time so we're confused
> about
>>> advice regarding boiling fuel. It's as if the fuel is being pushed
> from
>>> the electrical fuel pump straight thru the carb, forming a
> mini-geyser
>>> at the front. Doesn't happen all the time but enough where driving
> the
>>> car is a dicey proposition.
>>> Any thoughts or advice? Thanks
>>> Tom Di Iulio
>>> Denver, CO
>>>
>>>
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