>
>
> I've been having a lot of trouble starting my '75 MGB cold, and even once
> it's warmed up it often dies at low idle. When I bought the car it had
> all it's emission controlls striped out and now has a Weber DGV carborator.
> ...
> weekend I changed the plugs and checked the sparks from the distributer and
> now all are sparking adequately. I also took out the carborator and found
> it to be very dirty and oily. I have since completely cleaned it with
> gasoline and reinstalled it.
> ...
> David
>
The first place I would go would be ignition. Since it appears you covered
this, we'll go on to other things. in no particular order)
Check that the choke is closing fully cold, and opening as the engine
warms.
Valve adjustment. Specificly you'd be looking for a tight intake valve.
Manifold gasket. DGV's are heavy and hung a long ways from the head.
Toss in those silly cardboard gaskets included with most headers and
the dynamic shakings of a four cylinder, and you have a self-loosening
manifold. Even with a stock gasket, it will eventually beat around
enough to cause a leak. Tighten the bolts or change the gasket as
necessary.
Booster leaks. With the engine running, stick your head down the drivers
footwell and listen for hissing from the brake pedal area. If you
hear hissing here, replace the booster. Next spray carb cleaner
(or whatever you use for vacuum leak detection) at the joint between
the booster and master. If a leak is evident, replace the cup seal
between the booster and master. As far as I know, this seal is only
available by buying a master cylinder rebuild kit. (this info and
test applys to TR7's also)
Primary slow run jet plugged. This is a common problem on *normal*
Weber installations (Fiats). Normal setups use a jet in the .40-.50
range. Typically, MGB's with DGVs end up with a jet around .70, so
they are much less prone to plugging. Remove the jet and blast it
and the jetwell out with carb cleaner and/or compressed air.
Manifold heating. The most common MGB DGV manifold has a token water
heating lug cast into the bottom. Make sure this is hooked up, and
plumbed into the old choke water lines, NOT the heater line. Also
make sure the engine has coolant in it. Lack of manifold heating
should not cause a starting problem, but will cause poor slow
running, especially cold.
And now we're back to the ignition... :>
Randy
|