water pressure gauge question...

[relocyo]

1978 85 hp johnson #85ml78c on a 1977 glastron gt-150... the dash has a water pressure gauge that is inoperative ive followed the tube from the gauge to the engine case where it sits unhooked and routed to the port side of the motor, its a hollow tube almost identical to the pitot tube.... its routed on the very bottom of the housing, but yet there is nowhere to hook it up in the vicinity of where it is (with little to no slack) where does this thing go? or did the PO do something wrong using the tube... i dont have a clue... any ideas my friends??

 

[Dabbler_E]

Re: water pressure gauge question...

Mine attaches to a T fitting, the 2 other prongs of which lead to the motor and to the telltale hole.

 

[relocyo]

Re: water pressure gauge question...

hmm interesting, the fella at west marine had said it should be near or on the tell tale, problem is that the tube is on the port side and the tell tale is on the starboard side... i wonder if PO'S had removed it for some reason??? is the tube on yours hollow like the pitot tube?

 

[GatorMike]

Re: water pressure gauge question...

My tube runs down the port side along with the fuel and electrical lines, then it wraps around behind the exhaust cover where a water tube comes out of the lower port side of the cover. That tube runs up and over the exhaust cover then down the other side to the teltale. The hose from the pressure guage plugs into a T in that hose.

 

[relocyo]

Re: water pressure gauge question...

ok thanks for the input.. so does that mean i need to install a T to the tell tall hose its like 1/2 inch in diameter so i need like a T that accomadates the 1/2 inch and then the tiny tube that runs to the pressure gauge? seems to me that water would flow thru the gauge tube all the way up to the actual gaue? that doesnt seem right but then again i dont know... seems odd that to get a reading at the dash that water has to flow from the tell tale tube all the way to the dash gauge?? ill try to post some pics 2morrow if that would help... thanks again yall!!!

 

[F_R]

Re: water pressure gauge question...

The gauge responds to pressure inside the tube. The tube is closed-end at the gauge end (the gauge is the closure). So, water only goes part way up the tube, till the air pressure at the head end is equal to the water pressure pushing it up there. That is the same way that a speedometer works. Don't fear, even if the water were to go all the way, the brass gauge guts will survive.

Advance Auto Parts has some nifty plastic tees. Check them out, may be just what you need. Cut the tell tale hose, insert the tee, and the gauge hose to the other leg.

 

[GatorMike]

Re: water pressure gauge question...

If you want to see if the gauge actually works just blow on the hose. It's interesting but I posted about the pressure gauge in my boat earlier this evening. I didn't know if mine was working so I blew as hard as I could on the hose and was able to move the gauge about 5 psi before my ears started popping. LOL I am sure you could use some kind of pump and save the ear drums if you wanted.

 

[relocyo]

Re: water pressure gauge question...

lol... ill give that a try... but maybe with my compressor =)... ya know i think i tried that with my speedo and popped my ears a while back.... haha...