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Hi, does anybody know what fuel pressure I should run the HIF44 carb at?
Just flashed up the new Facet pump and Filter King pressure regulator and I think the pressure is too much for the carb as the fuel leaked out of the float chamber cover !!
So, I am thinking the pressure as set by the Malpassi factory is too high for this carb.

Agree? or not?

Any pointers would be a great help

Thanks

Dave

I think the electric pump on my Mini used to run at 2.5-3 psi, I have never tested pressure on my Midas, it is however only a little, low pressure cube type pump though.

hmmm, this cylindrical facet pumps out a lot more than the cubes I reckon !!

I think I might have to trial and error it and reduce the pressure progressively so that the float is not overcome and yet does not starve the engine at speed !

What size line runs from your tank? If you double the pipe diameter the flow increases more than four times for the same pressure.

You need a very low pressure, since it only needs to keep filling the float chamber. I had a similar problem with my electric pump. The float needle just couldn't close the chamber and the fuel was pumped out via the overflow tube. I decreased the voltage over the pump to 9V by adding a parrallel resistor since I can not adjust the pressure on my pump.

streetsy wrote:What size line runs from your tank? If you double the pipe diameter the flow increases more than four times for the same pressure.

thanks for this information, very useful !!

Have had the car running today - whoopee - and it seems to have settled down now....keeping an eye on it though !

Yes keep an eye on it. If it pumps out fuel again your car will certainly catch fire. Whenever I start the car I only put the ignition on. The pump starts running, but the engine is still silent. I then check if the fuel stays in the carb (I can hear it clattering on the street and ofcourse the smell) and only then I start the car. I have a pressure limiter with return to the tank, but am not sure it always works properly.

axshack wrote:Hi, does anybody know what fuel pressure I should run the HIF44 carb at?
Just flashed up the new Facet pump and Filter King pressure regulator and I think the pressure is too much for the carb as the fuel leaked out of the float chamber cover !!
So, I am thinking the pressure as set by the Malpassi factory is too high for this carb.

Agree? or not?

Any pointers would be a great help

Thanks

Dave

That's pretty much the same set up as I have on mine, I think your initial problem lies with the carb as you shouldn't be leaking fuel, time for a rebuild kit, or a revisit if done already.

Cant you just plumb in a return to the tank? Empty the tank, swill it with water and leave some water in while you braze some pipe to the top then empty the tank and leave it to dry for a day or 2. For double reassurance I put some chemical metal round the tube as well

Just a thought, is the float level set correctly?