Mercruiser 6.2L Closed Cooling Check Valve Question

[Greg_E]

I have twin Mercruiser 6.2L MPI MIE Horizon engines. The older 2003 engine has the Cool Fuel 2 and the check valve between the transmission cooler and high pressure fuel pump module cooler
The newer 2007 engine has the Cool Fuel 3. and does not have a check valve.
Just curious to know what the purpose of the check valve is on the older engine and why it it's needed on the older engine, but not on the newer engine.
I will be be replacing the the fuel cooler as a preventive maintenance measure and if the cooling water flow check valve doesn't serve a useful purpose, I would like to eliminate it.
Thanks for any replies.

 

[alldodge]

All the coolers is to reduce/prevent vapor lock

The check valve helps keep water in the hose when the motor is OFF. The Gen 2 cooler is low on the port side and full cooling water and only a loop of tubs to cool fuel. When the motor shuts off some water will drain out

The Gen 3 is a module is a box within a box. The fuel pumps are submerged in fuel and the outer box fills with water. The fuel cools the pumps and the water cools the fuel. The water going thru the box is accomplished by venturi action (in thru the bottom and out thru the top).

My personal opinion, is if I ever have a boat with a fuel module, I'll change it to the Gen 2

 

[Greg_E]

OK. Thanks for the explanation.
I will be keeping the check valve when I replace the fuel cooler and transmission cooler and hoses.

I share your opinion of the Cool Fuel 3. I had to replace the Cool Fuel 3 on the newer engine last season. It was a corroded mess. The improved version is just a bandaid at best.. An expensive one.

Thank you AD

 

[Bt Doctur]

Just tossing this out there, has anyone tried cooling the fuel before the pump with a PS or oil cooler unit?