Bobby Bloyed wrote:
>
> I have a 1976 triumph spitfire. The mechanical pump failed and the previous
> owner replaced it with a electric fuel pump. My question is will the
> electric fuel pump increase the fuel pressure to the carb and cause the
> mixture to be slightly rich at idle? I have rebuilt the carb and I also
> blocked off the choke circuit to make sure it was not causing a problem. I
> also completely closed the decel valve to make sure it is not leaking. The
> vehicle does not have a catalyst as it is a Federal Vehicle. On a emission
> analyzer I see(with the air pump connected):
>
> Idle
> HC 460
> CO 3.6%
>
> At 2500
> HC 63
> CO .46%
>
> Any assistance would be appreciated as I have to pass a california DYNO
> test. Thanks Bobby.
Most electric fule pumps need an in-line regulator to keep the pressure
constant and at a lever that is required by the carb(s). That is
generally around 2.5 to 3.5 psi. Because most pumps are delivering much
higher pressure than what is required, the result would normally be
overflow of the float bowls and not rich idle. But I suppose anything
is possible.
Regards,
Joe
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