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Restricting fuel preesure
dave1888 - 23/3/08 at 05:53 PM

I have my sva on thursday and have discovered that my carbs are over fueling caused by the fact that my R1 pump is putting out 3psi and the carbs are gravity fed. I will order a fuel regulator on tuesday (monday holiday) but as a back up plan in case it doesn't arrive in time is there any other way i can restricted the pressure to the carbs as a temp get thru sva solution.
yours hopefully Dave

Guinness - 23/3/08 at 06:16 PM

Erm not a quick fix, but could you cobble the following together?

Use the fuel pump to deliver fuel to a header tank in the engine bay, from which fuel feeds to the carbs, then have a return to the tank for the excess? Like a fuel injection swirl pot?

More mad ideas to follow.

Mike

Mike

Jon Ison - 23/3/08 at 06:18 PM

quote:
Originally posted by Guinness
Erm not a quick fix, but could you cobble the following together?

Use the fuel pump to deliver fuel to a header tank in the engine bay, from which fuel feeds to the carbs, then have a return to the tank for the excess? Like a fuel injection swirl pot?

More mad ideas to follow.

Mike

Mike



I would say thats the answer to get pressure down to below 3psi could cause starvation as there I would imagine be very little flow ?

dave1888 - 23/3/08 at 06:27 PM

This is just a back up plan hopefully if i order a regulator on tuesday it will arrive on wednesday.
Would it be possible to fit a restricter in the main fuel line say a piece of tubing with a smaller diameter hole in than the hose.

[Edited on 23/3/2008 by dave1888]

Jon Ison - 23/3/08 at 06:46 PM

IMHO it will have to be one hell of a regulator to regulate down to what ? 1/2psi ? 1psi, what pressure do your floats open at or more to the point how much pressure can they push closed ?

If you can find one to suit job done but I personally would be worried about the reliability and repeatability of a regulator function at such low pressures.

I think the restriction you mention would only disturb flow rather than pressure.

snapper - 23/3/08 at 07:25 PM

Restricting the diameter of the pipe will not reduce pressure, just flow.
I use a Filter King/ Malpassi regulator and used a small cheap pressure gauge to set up.
The regulator can easily reduce pressure from Zero to what is needed.
Remember that gravity is 14 psi( the gauge probably does not read any atmospheric pressure0 so a little above 1 psi will be OK, the fuel delivery that you need is just below what will defeat the float valves

[Edited on 23/3/08 by snapper]

mark chandler - 23/3/08 at 07:26 PM

If you have plumbing for a fuel return then you can tee off to the carbs and have a restriction in the return, small carb jet etc. This will bleed off the pressure, when the float drops most fuel will still find its way to the into the carbs as its the bigger hole.

Regards Mark