1994 Freshly Rebuilt 7.4L Temp??

[Juttmk]

On the lake now 4th trip out.
Freshly rebuilt 1994 7.4l Mercruiser
7 hours on engine
Runs perfectly fine, but noticed tonight that when I go to start boat after sitting for 10 minutes the temp gauge is at 175.
Port side riser 210 degrees after 10 minutes
Starboard 190 degrees after 10 minutes

A little online research suggested idling for 30 seconds prior to shutting down. Initial check showed temps below.
Port side 130
Starboard 130

With in 5 minutes the portside riser is 200 degrees
Starboard 150.

I can hear some gurgling after shutting down.

Valve covers 160
Oil filter 165
Exhaust manifolds 200 each
Thermostat housing 155

Shooting IR on everything now!!

 

[tpenfield]

It does not sound like you are getting any where near enough water to the engine. Tell us a bit more about the engine (original serial number, and outdrive type).

I would assume you have a Bravo outdrive with the sea water pump on the engine. Maybe check to see if the impeller is intact, and that you are getting good water flow through the oil cooler(s) up to the thermostat housing.

Typically the top of the exhaust elbows should be 100 F or less with the IR gun.

 

[Juttmk]

1994 Bravo 7.4l
Engine Serial # OF126634
Bravo 1 outdrive
OF183087

I had a chance to look at the risers and manifolds just as the engine was in the final assembly stages and everything looked good. What gets me is the thermostat housing temperature matches dash gauge, which doesn't appear to be out the normal. I'm trying to figure out as to how the riser would get hotter as the boat sits not even running. Looking at the engine temp, it appears the thermostat is cycling properly. will look at the impeller a little later and disconnect a few hoses to see how things are looking.

 

[AShipShow]

Not sure what exact cooling setup you have but you can see in this picture, the risers are cooled by the raw water sytem that bypasses the thermostat so like stated above, I would make sure your impellar is in good shape.

 

[Juttmk]

The water exits the impeller housing outlet and goes through an oil cooler to the manifold. Once the water hits the manifolds it's diverted to the exhaust manifold and risers.

I went ahead and back flushed through the oil cooler, but was very difficult since the discharge hose from the impeller housing was tucked down in the bulge. Should I check the impeller or run the engine and check the flow rate from the cooler to the water manilfold on top of the thermostat housing? What is the flow rate at the manifold?