35 & 40hp Mercs fuel pump cooling hose question

Jul 12, 2008
I picked up 2 ea 1988 35hp mercurys for parts to repair my Old 40 thunderbolt.I needed a prop gear housing and it interchanged perfectly. The guy I purchased from said one engine was fr parts and the other ran but no water flow. I have not tried starting it yet but I am a little miffed and I've looked here, elsewhere online and every engine diagram I could find but no answer. All power head blocks are the same on all three engines but the fuel pumps are each different.
The 40 has a cooling water hose that runs from bottom rear port of power head, around the back and into the bottom rear of fuel pump, then hose rear top of pump to telltale, of course it has the fuel lines in and out.
The complete non cooling 35 has all four connections on fuel pump but only fuel lines are hooked up and one hose from starboard upper connector of power head to telltale.
The 35 "parts only" engine fuel pump only has three connectors, the fuel lines are hooked up and pee tube is missing.
If the crankcases and water flow the same on these three, why are cooling hoses configured all different? I am completely baffled. You guys here now your stuff, help me to understand!!
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