thermostat question
 

I took the boat out today and we put a computer to verify the temp Low and a ECM code stating so
120 range on a EFI 502 Volvo sorta looks like a HP500 and uses the same intake system. I need input
on this I see that there is a Second thermostat in the upper housing, and I found NO thermostat in the manifold the One on the photos I just picked up from
Chris Martin.

this is the housing it has a thermostat in the top looks like it controls the water to the manifolds.

top of housing ,, the 2 upper connections go to the manifolds the Brass one is the fuel cooler line
and the med sized one on the left comes from the
sea pump, the large one from the circulator pump.
the new or missing thermostat touches the bottom of the one in the housing ??? is this a issue

fits but is close or touching the upper thermostat

Not familiar with that set up, but it looks like it is in upside down.

you are adding a thermostat in the wrong place you have to replace the thermostat that is in the upper part of the that housing.Pull the brass spacer out of the housing to remove it, sometime it is tough to get out and you may damage the sleeve and may have to replace it but if you put it in the lower part of the housing you will have over heating problems.

I dont see no way to remove the one in the upper part
it looks like its built in ,, water can flow into the housing and to 2 connections without the thermostat I was given the upper one seems to control flow to the
exhaust manifolds and nothing else, Im lost the motor will not heat up. and ECM code is generated.
I did check the upper t stat with hot water and it opens up,,, could the sending unit for the ecm be bad and telling the computer its cold?

yes I turned it upside down to show you