<VV> Healthy pumps?

[Frank DuVal]

But the spring IS the regulating mechanism in the pump. There is no other regulator. Just like the oil pressure regulator is the spring pressure. The air regulator on your air line uses the spring pressure to regulate the pressure. The fuel pump is pushing pressure against the inlet valve in the carb, which is resisting with the float pushing on the fuel level. So, the bigger the spring constant in the pump, the harder the force on the float. None of the check valves stop the fuel from leaving the pump through the outlet fitting.

Daniel's write up is good.

Also, another Corvair person wrote an article for Skinned Snuckles magazine waay back in November of 1994 on how fuel pumps work. Our own John Moody (one of the Bentwrenches) of Washington, DC.

"This spring is the */ONLY/ */source/ of fuel pump pressure to the carburetor. Nothing else controls fuel pump pressure (in a "standard" system)."

I will be happy to furnish a picture (scan) of the article for anyone interested.


Frank DuVal



corvairs wrote:

> Frank, I would be inclined to think that if the spring was made 100 
> times stronger then it still wouldn't matter because of the 
> self-regulating mechanism in the pump. Lon
>
> www.corvairunderground.com
>
>
> Frank DuVal wrote:
>
>> Ahha, but the spring is the source of fuel pressure. Put in a heavy 
>> spring and the pressure will be too much. That is why just changing 
>> the spring in the second case worked.
>>
>> I ran into this first over 30 years ago on a pump for a Wyllis 
>> Jeepster. Three used pumps to chose form, one too weak ran out of 
>> fuel above an idle), one waaay to strong (flooded out the top 
>> cover/vent) and one just right. I took them apart to see and the 
>> spring tension was noticably different.
>>
>> Frank DuVal
>>
>> corvairs wrote:
>>
>>  
>>
>>> Grant - The design of the mechanical fuel pump for the Corvair makes 
>>> this kind of impossible, unless someone is making/selling a version 
>>> of the pump that I have never heard of.
>>>
>>> It's a simple design that is intended to "cycle" (that is, not pump 
>>> gas) when a minumum amount of back pressure is encountered. If you 
>>> look at the internals you can see that the pump has no other way of 
>>> determining when to push fuel or not. And the demand for fuel 
>>> constantly changes.
>>>
>>> I would look elsewhere for the cause of the problems.
>>>
>>> Lon
>>> www.corvairunderground.com
>>>     
>>
>
>