1996 130HP Evinrude V4 looper water pressure gauge install question

[aok47]

Is the my water pressure gauge installation correct on my 1996 130HP V4 Evinrude (looper)??
It has the line that goes to the water pressure gauge coming from top LHS of engine block (first photo) and come off a t-piece that goes to the tell tale (second photo).



I'm trying to troubleshoot an overheat alarm i only get at idle, I have confirmed temps are high so not a false alarm. I have replaced thermostats and put in a completely new water pump kit but overheat still occurs at idle.
Next thing i was going to do was try dropping the leg, inspecting the copper pipe in the leg and flush up through it and then down through the thermostat housing in the cylinder heads.

Open to any other ideas...

Cheers
AK

 

[ct1762@gmail.com]

Indcator hose pressure location looks fine. On the overheat: Did you replace the rubber t stat grommets? they must be sealed. if they leak, it will overheat as it cannot create the pressure it needs to fill up to heads. verify both t stats are opening with some hot water gradually warmed up. just the tiny top piece pops out to press itself against the housing and let water in against the spring seat. Are you diagnosing this in the water or on the garden hose? if the idle RPM is too low, it can also get warm as it cannot pump enough water. should be 900rpm where you take the temps so a fast idle.

 

[aok47]

Yes, I replaced the rubber grommets when I did the thermos.
The motor overheats on muffs and in the water. Last test was actually on the water and I was idling out of the harbour at 2,000rpm when I could see the temperature rising (i have stuck on thermocouples near the temp sensor to independently confirm temps and rule out any overheat alarm wiring issue) and it didnt take long for the overheat alarm to come on. No issues when I get on the plane and water is being forced through at a higher pressure

I pulled out the thermos again and can confirm they expand as i heat up a saucepan with water.

 

[ct1762@gmail.com]

well something MUST be leaking at idle in the t stat housing. The plastic t stat seat could be it, or the grommet got rolled, or the metal ring is missing which (i think) compresses the spring to the proper tension. other thing to do would be to remove t stat housing and make sure water is getting to heads at idle. did you put the 0-ring behind the pump housing in?

 

[aok47]

I checked and dbl checked everything in the thermostat housing and the install, nithing looks suspect.
Found this though:

I think I cooked the impeller from trying to run in a tub but water was only inline with cavitation plate... that won't help cooling at idle
With the gearbox off I attached the garden hose directly to water intake tube inside midsection and ran the motor.
Temps stabalised at 115°F on starboard top cylinder versus 75°F on port. Concerning???

 

[clemsonfor]

Yep that impellor is shot!

 

[clemsonfor]

115 seems normal at idle with all that water going through the motor. 75f seems awfully cold for it to have been running!! Without it actually running in the water I wouldn't worry too much put it back together with fresh impellor then run it on the water and see what you get. Shoot the heads at idle in the water and see what each side it then and then go for a wot run and come off plane and see what each head is. If still pretty uneven maybe look at t stats again?

 

[aok47]

before putting it all together i thought i'd swap the complete thermostat assy (thermostat, spring, grommet, everything).
Ran outboard and found that the temperatures in the cylinders swapped!
I'd verified the thermos were opening in warm water so i thought... let me swap the thermostat spring (0336179) in the side that is running cold... did that with a spare spring i had from an old motor and the temps are within 9°F, versus 36°F difference before swapping the spring.
Interesting!

 

[clemsonfor]

before putting it all together i thought i'd swap the complete thermostat assy (thermostat, spring, grommet, everything).
Ran outboard and found that the temperatures in the cylinders swapped!
I'd verified the thermos were opening in warm water so i thought... let me swap the thermostat spring (0336179) in the side that is running cold... did that with a spare spring i had from an old motor and the temps are within 9°F, versus 36°F difference before swapping the spring.
Interesting!

Sounds like you had a defective new part...

 

[ct1762@gmail.com]

before putting it all together i thought i'd swap the complete thermostat assy (thermostat, spring, grommet, everything).
Ran outboard and found that the temperatures in the cylinders swapped!
I'd verified the thermos were opening in warm water so i thought... let me swap the thermostat spring (0336179) in the side that is running cold... did that with a spare spring i had from an old motor and the temps are within 9°F, versus 36°F difference before swapping the spring.
Interesting!

well yes. if the spring isn't stiff enough, it will unseat the grommet as I had mentioned something must've been leaking! if they leak, you are screwed as the water pump can't get enough pressure to tip it up and over down into the heads. also these new t stats are horrible. the old ones with mercury would last 2 decades. now you need to replace them much more often. the little pin on top must be tested/proven to pop out or it wont push itself against the seat spring and let water in, too.