water psi ?

[daytrader]

what causes the water psi gauge to show an erratic reading when running at speed? I have replaced the poppit valve and thermostats. Am I running to high? (vector, 2.4 merc, about 1 1/2 in. below pad) am I getting "arreated" water pressure? thanks for any replies, Daytrader

[Cobalti]

Check that you don't have a leack somewhere in the plumbing,

No dirt build up in the plumbing.

[WATERWINGS]

I put a BRAND NEW impeller in one time, and it did the same thing.

Turned out that the hub in the impeller was spinning and it wasn't keeping the pressure up.

Changed out and put the old one back in, it was cured, so, another NEW one, and all was well.

Just a thought.

[MarkHP]

When you say 'erratic reading' what specific readings are you getting at what RPM? I am curious as I may have similar issues.

[daytrader]

Mark, I dont run that hard, the readings usally occur between about 3 to 5k rpm, I was just thinking that maybe the water psi is not always a "steady psi" but gets "arreated" at higher rpms, I had put in a new pump and gaskets but not a wear plate, also I only get 10 to 12 psi at speed. (wich opinions on how much psi is enough seem to vary from 10 minimum to about 15 to 18 at speed) Hope u figure your problem out, Regards, Gary oops, just realized I didnt really answer your ? the needle on the gauge jumps back and forth between about 6 to 14 psi

[daytrader]

John, thanks for the reply, what combo are u running these days? Gary

[SAMMYBOY]

From my Mercury Manual 2.5 200 HP

Water Pressure
Idle 1.0 – 3.0 PSI (6.8 – 20.5 kPa)
Poppet Valve Opening 4 – 9 PSI (27.4 – 61.6 kPa)
W.O.T. 12.0 PSI (82.1 kPa) Minimum

Poppet Valve Opening 4 – 9 PSI (27.4 – 61.6 kPa)

Poppet valve flutter/water pressure
drop does not stabilize prior to 2500 RPM 4 – 9 PSI (27.4 – 61.6 kPa) be-tween 1000 – 2200 RPM
•Wrong poppet valve spring
•Low output water pump
•Inlet restriction
•Broken diaphragm in poppet
valve
•Severe internal leak
•Defective poppet valve seal

I hope this helps....

[great adventure]

what I have learned from water pressur gauge is... the water psi
at the gause is different from yamaha to mercury. if you are running
the motor with nose cose it will be 10 to 12 psi and if you fix transom
water pick up it will reach 15 psi and if it is 0 psi that means its not taking
any water.. and finally if it is 30 psi it means the motor is taking water but the outlet is blocked.!!

on the other hand becarefull when you fix the transom water pick-up
always hold the hose connected to the lower unit with a stanless-steel
spring to avoid cut off while running at hi speed and also try to fix s-steel
mish inside the pipe of the transom wate pick-up otherwise any one
throw his cigarette in the sea you will find it in your block or both heads

good luck

happy new year and merry christmas