What is the "correct" fuel pressure?

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GRCameron
United States of America
Posts: 158
Joined: Tue May 27, 2014 7:32 pm
Location: Yarnell, AZ

What is the "correct" fuel pressure?

Post by GRCameron »

What is the correct fuel pressure I should be measuring at the carb inlets? The service manual specified minimum fuel pump performance at 4000 rpm as 24 liters (per hour, I'm assuming) and 0.3 bar pressure (4.3 psi). What pressure do you measure with a properly working pump under normal conditions?

I intend to replace the mechanical pump with an electric pump and adjustable regulator. I need a pressure to set things up.

Thanks!
George Cameron
Yarnell, AZ
1979 Pinz 710M
Molon Labe
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Jimm391730
United States of America
Posts: 1456
Joined: Wed Apr 14, 2004 10:58 pm
Location: Idyllwild, CA

Re: What is the "correct" fuel pressure?

Post by Jimm391730 »

Most carb setups work best at 3-5psi. But I'd aim for the 4.3psi as you stated.

Pressure too low and the bowls will not stay full at full throttle; pressure too high and the bowl levels will be too high as fuel can squeeze past the "closed" needle valves.
Jim M.
712W and 710M
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