1997 130tlrv

[travjudy1]

I am getting only about 1-2 psig of water pressure (gauge, tubing etc are all ok). I have changed water pump impeller and housing. Pulled heads and head covers to inspect for fouling - all clean. I now suspect that water tube may be cracked/broken or tube seals bad.
How do I remove the water tube that runs up from the pump discharge to the power head? Should it just pull out once the lower unit is removed?
Thanks,
Travis

[boscoe99]

At what RPM are you getting 1 -2 psi?

Is the over temperature alarm sounding?

[travjudy1]

water pressure

1-2 psig at 4000rpm. No reading on gauge at idle or up to about 3500rpm. I do not overheat and the tattle-tell shows adequate, but not strong, water flow.
Thanks

[amahaork]

I don't understand how water gauge works: is it water pressure inside gauge moving gauge needle, or needle calibrated for air pressure compressed by water inside tubing?

[boscoe99]

The gauge itself works with air pressure.

The water pump creates water pressure. Water pressure is fed to a tube/hose that runs to the gauge.

Water can only move so far up the tube since the system is closed. Water pressure is converted to air pressure. Air pressure acts upon a Bourdon tube within the gauge that moves the needle on the gauge. The extent of the needle movement is a function of pressure on the tube.

[almetelo]

1-2 PSI or 10-20 PSI?

I may have more or less the same problem if is a problem

I recently installed a water pressure gauge and a water temperature gauge on my dash board from my F100.
Since the block of this motor just have one bore for one of this options I ordered an adapter on a machine shop so I could fit both.
Water temperature seems to be working good but water pressure NOT (I guess) however I dont know how is this supose to work (I know that are no reference values since each motor must be diferent)
My gauge is in Kg/cm2 which
1 kg/cm2 is 14 PSI
1,5 kg/cm2 is 21 PSI
2 kg/cm2 is 28 PSI

When I accelerate to get on plane the needle oscillates several times (even for a while after plane) than stabilizes a little over 1 kg/cm2 or around 16PSI at about 3500rpm's.
The max pressure I can get is a little less than 1,5 kg/cm2 or 20 PSI.
At WOT pressure is about 1 kg/cm2 or 14 PSI.

I dont know if this is suposed to be normal (what ever that means but is not what I was expecting) my guess is that water pressure is low (thermostat is 4 months old, motor is flushed regularly, if I just connect the water pressure to the block bore acts exactely the same way.

[boscoe99]

[QUOTE=almetelo;95794]1-2 PSI or 10-20 PSI?

I may have more or less the same problem if is a problem

I recently installed a water pressure gauge and a water temperature gauge on my dash board from my F100.
Since the block of this motor just have one bore for one of this options I ordered an adapter on a machine shop so I could fit both.
Water temperature seems to be working good but water pressure NOT (I guess) however I dont know how is this supose to work (I know that are no reference values since each motor must be diferent)
My gauge is in Kg/cm2 which
1 kg/cm2 is 14 PSI
1,5 kg/cm2 is 21 PSI
2 kg/cm2 is 28 PSI

When I accelerate to get on plane the needle oscillates several times (even for a while after plane) than stabilizes a little over 1 kg/cm2 or around 16PSI at about 3500rpm's.
The max pressure I can get is a little less than 1,5 kg/cm2 or 20 PSI.
At WOT pressure is about 1 kg/cm2 or 14 PSI.

I dont know if this is suposed to be normal (what ever that means but is not what I was expecting) my guess is that water pressure is low (thermostat is 4 months old, motor is flushed regularly, if I just connect the water pressure to the block bore acts exactely the same way.



Your water pressure looks just fine. Only published Yamaha specification is for 11 psi minimum when at WOT. Pressure is just a means to an end. With the end being engine cooling. Better to have a cool engine with 5 psi water pressure than an over temping engine with 35 psi.

That is a very clever fitting. Your idea or the machine shops idea? Is it available for those that might want to get one?

[almetelo]

Hi Boscoe!

It was my idea...(my thoughs was the 2 gauges or none) lol
I just told them what I wanted and said that should be lowest size they could do it so I could fit it on that small place.

If is working good even better...
I just was expecting higher water pressure.

[amahaork]

if you temporary close pee-hole with finger, will water gauge pressure jump up? maybe need inspection of bypass water valve? (if you have it)