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Re: [T3] Carb Problems


On 24 Sep 2006 at 15:55, Steven Cooper wrote:

> I've just got my fasty going again after an extended rest.  I think I've 
> fixed the flooding problems she was having by installing slightly thicker 
> gaskets under the fuel pump to drop the pressure a bit.  It think it was 
> running at too high pressure causing the needle valve to leak and overfill 
> the bowl causing flooding.

Small changes in the pump output pressure really can't make 
significant changes to the richness. The float in the carb bowl is so 
large and the orifice it is trying to close is so small that the 
control "gain" of this system is quite capable of overwhelming any 
overpressure. Clearly, there will always be some small effect, but I 
don't think it will ever be big enough to be noticable.

The main reason for setting the pump gaskets is to make sure that the 
pump is being asked to travel over a range that will allow it to last 
a long time. The wrong range of travel is hard on the pump diaphram.

> Left hand screw
> 1) Screw in - all the way in until it bottoms out - makes no difference
> 2) Screw out - all the way out, makes no difference.
> In other words, adjusting the left idel mixture screw makes no difference to 
> idle speed or engine running.

Sounds like the idle circuit in that carb is not letting any gas/air 
thru. Make sure the elec. idle jet (if you have them) is working and 
then go thru the carb and make sure all the passages are clear.

> As I said, she idles and revs quite happily at 1000RPM when the engine is 
> not loaded ie in neutral or park.  But as soon as I put her in R or D, the 
> revs drop dramatically, she coughs and splutters and doesn't want to move. 
> If I put my foot down enough, she eventually gets to apoint where suddenly 
> she surges forward (or backward).

Again, this sounds like it's basically just running on 2 cylinders 
until you open the throttle a bit and let air thru the main circuits 
of both carbs.

-- 
*******************************
Jim Adney, jadney@vwtype3.org
Madison, Wisconsin, USA
*******************************

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