DOUBLE "D" & LV

Being a 90hp, it does sound like a pressure relief issue not the water pump.

Georgiaboy

turned out to need a replaced water pump and impeller. earlier this year when I had motor serviced, i suggested replacing these but the mechanic assurred me i had another year. that was not to be. back ready to hit the water now.

Tuna Man

clap:clap Cheap fix, well not a arm and a leg.

Curtisimo81

what does the popit valve do? My motor has ran hot a couple of times but when it does it quits peeing completely and steam comes out of the pee hole. If i shut her down and start her back up everything is normal again. Only got a horn once for overheating. Its a 90hp evinrude.

Tuna Man

I could be off base here but my thinking of what a pop it valve is used for in an outboard is to relieve water pressure from the water pump until the thermostat opens as it is closed when cold. The valve will hold some back pressure and relieve the strain on the water pump.

I had an old Merc 65 3 cyl years back and that engine would trash the top cylinder time after time. I got so tired of rebuilding the top cylinder I had to think of something to help me out. What I did was drill a hole in the top of the engine into the water jacket on top of the top cylinder, taped the hole and inserted a fitting that I could attach a hose to. I "T'edthe waterline hose and dumped cold water on to the top cylinder. Never had another problem out of it again. Before pop it valves were installed.

Curtisimo81

hmm i wonder if thats whats wrong with mine, maybe the popit valve... or a thermostat. i think i'm going to start with the thermostat

metal11

Tuna Man

The poppit valve actually doesn't open until about 1500 rpm's. It doesn't really matter what the temp is. If the motor is at idle the thermostats control the water temp, but once you pass about 1500 rpm's the water pressure is more than what can flow through the thermostat's so the poppit valve opens and controls the flow of water through the powerhead. So basically it comes down to if it overheats at idle check the thermostats if it overheats at speed then check the poppit. This all is considering that you have a good water pump.

Tuna Man

After doing a little research I find that the valve is installed and operates as you say..opens after a certain pressure created by a GOOD water pump. This opening will vary on engine makes, but usually around 1500 RPM and up depending on the water pressure created by the water pump. When this valve opens it allows MORE water flow through out the engine especially the power head. So if you have a water pump of questionable condition then the operation of the valve will be degraded, hence a lower water flow resulting in a possible overheating situation. So when a overheating condition occurs I see where you need to look for a restriction in the water lines, bad water pump, faulty thermostat and a sticking pop it valve (if so installed). Love to be more informed. Learning is a never ending process.