Yamaha 115/2008 water pressure guage won't function

[boneyjames]

I have a 1999 HydraSport with a 2008 115 4-stroke, with a new Faria W/P guge. Just installed it. Using the garden hose, cannot register a PSI. I have checked the line, no kinks, could it be not enough pressure is going through to register on the gage? I attached the air compressor hose to the hose I disconnected from the block, tried to see if it was clogged, nothing came out.

What is next ??

[boats.net]

It wont show water pressure at idle on a flusher, needs to be in water above an idle.