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Fuel Pressure


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The rear CD150 Stromberg on my Vitesse Mk2 engine often flooded and I traced this to high fuel pressure (around 6+ psi) from the new mechanical pump I had installed. I fitted a Petrol King pressure regulator adjusted down to about 2 psi and have had no problems since.

However, the engine bay of my Gentry was recently gutted by a fire which was probably caused by a fuel leak judging by the smell of petrol which preceded the fire. The seat of the fire appears to have been on the ignition side of the engine in the coil/alternator area. There was a short rubber hose joining the copper pipe which came out of the pump to the copper pipe along the side of the engine and around the front to the carbs. This was proper fuel hose, not old enough to have perished and I use Super unleaded to reduce ethanol effect.

With the pump pushing out 6 psi, being restricted to 2 psi by the regulator further along the pipe, what happens to the build-up of pressure between those two points? Could that have caused a fuel leak at the hose joining the two lengths of pipe?

During the rebuild I am considering re-routing the fuel pipe around the rear of the engine, away from the ignition. Has anyone else done that? I am also considering fitting a low pressure electric, or electronic pump, either SU or perhaps solid state e.g. Facet. I believe that the AUA25 or AUA66 Low Pressure SU operates at 1.5 psi and the AZX1307 at 2.7 psi. Does anyone have experience of using these pumps please?


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I don't know about your pressure problems however, I do know that people concerned about fuel overheating do re-route the fuel line behind the back of the engine with no problem. 

I have replaced the entire length of fuel line between pump and carbs with one line of rubber (R9) around the front of the engine. Rubber keeps fuel cooler than metal.

Brake fluid is guaranteed to ignite when dripped on exhaust manifold, while petrol is not. You were unlucky with your fuel leak and alternator spark.


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