pressure gauge

Bought a temp guage and a water pressure guage for my yamaha from boats.net, when ordering the I chose a sender thinking the guage must be electronic but I recieved a nylon hose which is ok but not the sender I was thinking of.

Does anyone know if this hose needs to be full of salt water to relay pressure well or can it be half and half or all air - does it matter??

Also if I was to fit both a temperature guage and the water pressure guage will I need to drill and tap a new hole? or did i miss the second fitting. I can only find one place manufactured to rig a sender/hose fitting.

Engine is a 1990 3cyl 2st yam 90hp.

regards,

snorri

[boats.net]

You can use either a water pressure gauge or a temp gauge on the 90hp not both gauges, there is only place on block for sender. I prefer water pressure over temp gauge. No the water pressure tubing does not need to filled with water to work.