[urq] Fuel Pump surge - still having problems

[Ado Sigal]

I believe that your problem is that under acceleration, the pump manages 
to draw the air from the fuel surface. Below 1/2 tank suggests this to 
be the case. A proper surge baffle of decent capacity, which Ur and most 
tanks with outside pumps are missing, would be a solution. (reason why 
in tank pumps don't have this problem, is because there is always decent 
surge baffle pool, and large pump intake close to the bottom). If you 
don't want to open the tank, other solution would be to return the fuel 
directly in front of the pump intake, instead of elsewhere in the tank. 
Simple longitudinal small capacity self bleeding cylinder (top line from 
the tank, bottom to the pump, and fuel return on the side) directly 
before the pump, should solve the cavitation and fuel starvation 
problem. In this scenario, the amount of fuel drawn from the tank would 
be only the amount of fuel used by the engine.

Regards,

Ado



Ben Swann wrote:

>Essentially what you say that I'm "flowing way too much fuel to return it to the pump
>unused" is how it is done usually.  If not I'd like to know.
>
>Still - I'd like to find out how to keep the cavitation from happening.  - 
>some point during running, the fuel starts to bubble and cavitation during running.  
>

I do notice it seems to happen more as the tank goes to below 1/2 - 
still a lot of fuel in the tank tho.

>Ben
>
>  
>