[T3] Fuel Primer.Switch..

[Jim Adney]

On 29 Sep 2018 at 10:44, Keith Park wrote:

> Yea, not sure what would hold it from opening properly except maybe an
> excessively stiff diaphragm.

If there had been some sort of crud or buildup on the diaphram, that 
might have done it, but it would have taken a lot and there was 
nothing.

I'm thinking a "rolling" clog in the steel return line in the pan. 
Consider adding a fuel system cleaner like SeaFoam to a couple tanks, 
if only as a preventative measure, just in case.

There's also a small vent hole to the chamber on the air side of the 
diaphram. It faces down and has to be open for the regulator to work 
properly. If that got blocked, and if the diaphram was some sort of 
plastic, then vapor that diffused thru from the gas side could have 
built up pressure on the air side, which would have increased the 
fuel pressure. If you have this problem again, you might try clearing 
that hole with a straightened paperclip. That hole might be hard to 
find with the regulator in place, but still less work than replacing 
the regulator.

And it still doesn't explain why you've had this problem twice and no 
one else has.

> And I do find it amazing that these diaphragms are still servicable after 50
> years in Gasoline, ethanol and all!

I'm afraid that was so long ago that I don't remember what the 
diaphram was made of. Was it metal or some sort of plastic?

-- 
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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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