I put a new hi-way motor (complete motor that I sealed and tested) on a broken ms390 a friend brought over. Now I have good compression and spark but no fuel. I can open the carb (HD 18b I rebuilt) and there is no fuel in the top making it through the needle. Metering lever is flush. All gaskets are new. I can pull a vacuum on the fuel line and get fuel up to the carb so that's clear. Everything is clear enough for carb cleaner to spray through. I put my vacuum guage on the impulse line and it goes from -.5 to +.5 psi. It felt weak to me, that's why I checked it. Does anyone know what a normal pressure would be.