Herald 1200 Fuel overpressure/excessive consumption/Malpassi Filter King regulator...

[Wagger]

I have tried 'Stretching' the spring to increase the pressure, and it did, from 1.25lbs to 2.1lbs. However, after running for a few weeks it is now 1.5lbs. The car runs ok, so I'm leaving it.

Make or obtain some longer studs for the mounting. Then you can use a thick gasket or spacer. Using an insulating spacer slows the heat transfer from the cylinder block to the fuel. A good idea in hot weather.

I have tried running from an electric pump at 4lbs. This works for a while but then a needle valve fails to close causing other problems. You need a fuel 'Shutdown' switch if pressure falls because of the dangers of leaks. (And leaks are costly).

 

[johny]

I wonder if we're getting confused here? Morgana if your carb doesnt overflow your pump and float valve are working fine and the system pressure is irrelevant. High pump pressure wont give high fuel consumption as the float valve maintains the correct level in the chamber and if it doesnt it overflows....

[Wagger]

Your are correct. However, if the float bowls and fuel pump get hot then fuel will evaporate when standing after a run. With twin carbs, this is rather more of a problem, especially if you do short runs.

[Pete Lewis]

On 24/05/2022 at 19:17, Morgana said:

where my fuel is going

missed this   in the firsted post  , ( must try harder )

one thing you need to check is how you check your consumption     if the oddometer roll is not recording full and accurate miles you can chase yourtail for ever 

as a slow mileometer gives you excess fuel useage results      it happes quite often 

Pete