One other thing I completely forgot to mention. Make sure you check
the internal return springs in the manifold side of the carb. You
have to take the carbs off the manifold to access them, and they are
under a plate. They break very often and when they do they can
intermittently block the thottle from returning even though you have
external return springs.
On Dec 8, 2006, at 8:11 AM, <triumph_marx@freenet.de>
<triumph_marx@freenet.de> wrote:
> Just a guess:
>
> When the engine revs won't come down quickly in most cases it is
> overriched
> mixture.
>
> Does your butterflies move freely?
> Does the linkage block on full throttle?
>
> I ran the Weber DCOE's only one time without soft mounting and they
> didn't
> perform well.
>
> I use overdrive springs for the anti-vibration mounting. They are
> stiff enough
> and last.
>
> Sorry that I can't help more.
>
> Chris
>
>
> ----- Original Message -----
> From: "Joe Guinan" <joeg@neb.rr.com>
> To: <fot@autox.team.net>
> Sent: Thursday, December 07, 2006 5:08 AM
> Subject: [FOT] Dellorto/Weber Fuel Foaming?
>
>
>> I'm running dual Dellorto DHLA40 carbs on my street/autocross
>> Spitfire, and
>> am having some troubles. These are quite similar to the Weber
>> DCOE, using
>> the same manifolds and filters but different jets (which of course
>> have to
>> be ordered from Europe) - so I'm hoping someone running DCOEs has
>> run into
>> something like this problem. I swapped from one set to another
>> and found I
>> had a several of the Thackery spring washers broken. I simply
>> replaced
> them
>> with nuts an bolts with lock washers. Now I'm having a hard time
>> getting
>> the engine revs to drop back down. When I shift, the revs
>> actually climb.
>> I am using the plastic anti-vibration mounts with the large O
>> Rings front
>> and back. I put on some new return springs, and the butterflies snap
> closed
>> on both carbs. I don't seem to have any air leaks around the
>> manifold to
>> carb junction. When running the engine without the vent covers on
>> the
>> carbs, I observe some "splashing" of fuel above the jets. That
>> might be
> the
>> source of extra fuel, but I still think I must have to find a
>> source of air
>> getting through as well.
>>
>> My question is, "What are the typical symptoms associated with
>> fuel foaming
>> from vibration of the carbs?" I may not actually be getting
>> foaming, but
>> simply getting some sloshing around that ends up with extra fuel
>> draining
>> into the throats of the carbs somehow. I do have another set of
>> thackery
>> washers, so will probably put those on first and see if the
>> problem goes
>> away. If it still acts the same way, I'm going to have to pull
>> this set of
>> carbs off the car and see if I can figure out what is going on.
>> Maybe
>> someone could point me in the right direction?
>>
>> I searched the FoT archives because I remembered a short
>> discussion of
>> thackery spring washers vs. rubber cushion washers. Mark B
>> mentioned
> using
>> the rubber washers on the top bolts where they won't get destroyed by
>> gasoline, and the thackery washers on the bottom mounts. Sounds
>> sensible,
>> and I'll be doing that when I find a source of rubber washers.
>> Will try
>> Fastenal tomorrow.
>>
>> Joe Guinan
>> Fremont, NE
>> Spitfires
>>
>>
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