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-   -   Help! Dellorto 45 leaking gas into the intake! (http://www.autobanter.com/showthread.php?t=39524)

Jan Andersson July 30th 05 09:16 PM

Help! Dellorto 45 leaking gas into the intake!
 
New engine, preparing for break-in. Used carbs.

dual Dellorto 45's.

One throat is puking gas all over the intake, leaks until the float
chamber is half empty. No other throat behaves this way. The
"neighboring" throat in the same carb is fine.

I replaced needle valve with brand new, lowered fuel level, and no
change.

I removed the top, and poured gas in . It started leaking immediately
after reaching what, half way full? ONLY one throat. Engine sitting on
level ground.

Where the hell is this leak coming from? if you know the carb well
enough, you'll know that there is a phillips head plug screw right above
each mixture screw. Removing that revealed the leak came from there, the
passage leading into that cavity from above.

What to do?!?! Need it fixed in less than one week! Before Friday's
cruising night and VW meet!


Jan

Randy July 31st 05 04:33 PM

Got it figured out yet ?
It's got my curiosity up.


Jan Andersson July 31st 05 08:44 PM

Randy wrote:
>
> Got it figured out yet ?
> It's got my curiosity up.


Nope. Taking this one carb back to the shop that sold it to me tomorrow
or later this week.
I really really needed it by Friday... argh

Jan

[email protected] July 31st 05 10:05 PM

If I needed something done before Friday,
I would start taking screws out, removing
parts, and find where the leak is.

Jen.


Jan Andersson July 31st 05 11:02 PM

wrote:
>
> If I needed something done before Friday,
> I would start taking screws out, removing
> parts, and find where the leak is.
>
> Jen.


I've torn it down to individual atoms several times now.

No visual problems; good, clean carb.

I am no newbie when it comes to carbs, and especially Dellorto DRLA.
This one just has me stumped.

I have it off the engine now and I'm calling teh shop I bought it from
several months ago. Heck it could have been last year. This engine has
taken it's time... ;)
Good thing I know the shop owner well and he kind of owes me a favor.

Jan

Jan August 1st 05 11:20 AM



New information, this may help someone else so I'll post it here.

Situation: 45 Dellorto DRLA leaks raw gasoline onto the throttle
butterfly and chokes the engine. Only one throat does this, the other
one stays dry. The leak is so bad that most of the float chamber will
drain into the intake manifold, and the leak is big enough to hydrolock
a 2 liter engine in less than a minute of standing still, whenever there
is fuel in the bowl.

The shop I bought these from, as well as another carb specialist shop,
both told me that while not very common, the DRLA line of carbs have
been known to suffer from this problem occasionally. The culprit is a
lead plug inside one passage near the bottom of the carb body.

There are several passages drilled all over the carb, and to be able to
drill a certain passage, it was required to drill "helper" holes from
another location at a different angle, that would intersect the main
passage. Once these helper holes were drilled, and the actual passage
finished, the helpers were blocked shut with a (soft) lead plug.
The plug that blocks fuel from entering directly into the idle circuit,
has broken loose on my carb and shifted. It's deep inside the carb, but
it is accessible after you remove (drill out) another, bigger lead plug
on the surface of the carb body. (near the accelerator pump and mixture
screw).

WHY this happened remains a mystery, it's been known to happen to brand
new carbs even. ONE reason could be excessive pressure.. from when one
cleans the passages with compressed air. Sounds logical, the pressure
could easily push a "wedge fitted" lead plug out.
Gawd knows I've given it plenty of air *after* I discovered this
problem :)
SUGGESTION: when blowing carb orifices and passages clean with
compressed air, do so from a distance so excess pressure has somewhere
to escape. Do not push the air gun nozzle against the hole.

The shop agreed to replace the entire carb for me, or hook me up with
someone who can fix it, of have it fixed for me. The other shop I used
because of their carb knowledge, also gave me a name and phone number of
a guy who has done this several times with success.

So, it's looking better now, I might be able to get the beast running
before Friday after all.


Jan


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