DIY GEN III Cool Fuel
 

I was changing fuel filters on my 6.2's and took some pictures. If some of you out there have not done this yet it will show how easy of a job it is. Literally takes 5 minutes per engine. I actually think the Mercury engineers had the customer in mind when designing this thing!:D

The cool fuel module is where they put the heat exchanger, fuel pump, filter, and water separator into one package. I believe the 496 engines are the same as my 6.2's. Only change the fuel filters on a cold engine. Mercury recommends that it be shut off for 12 hours, but that seems a bit extreme...

Pic1 - Exploded view of the generation III cool fuel module.

Pic2 - The module is on the front port side of the engine below the alternator.

Pic3 - First dicsonnect fuel pump from the engine wiring harness. Turn the ignition key and operate the starter for about 5 seconds to release any fuel pressure. The filter cap is held in place by three screws. The only tool you need for this job is a 10mm socket or wrench.

Pic4 - After loosening the three screws (they do not come out of the cap) pull up on the filter cap handle to unseat the o-ring. Let it sit in this position for a few seconds to allow the fuel to drain out of the filter cup.

Pic5 - This shows the filter/water separator assembly. Hold the filter cup and rotate the cap clockwise to remove the cap.

Pic6 - This is the filter cartridge. It seats on a post in the filter cup.

Pic7 - Filter removed from cup.

Pic8 - Here is all there is to the kit.

Pic9 - Had a little debri from the fuel tank, but no sign of water.

Pic10 - Wipe out the inside of the filter cup. The paper towel shows the residue that was in mine.

Pic11 - Don't be tempted to use a screwdriver or some other tool to remove the o-ring from the filter cap. You risk scratching the plastic sealing surface. Just dry the o-ring so it isn't slippery and grab it with your finger and thumb and pinch/slide it to expose some slack.

Pic12 - Grab the slack and pull it off.

Put on the new o-ring and put everthing back together. Slowly install the assembly back in the module to prevent spilling fuel. Tighten the three screws. The manual says 53 in-lbs (a little past snug). Start the engines and check for any leaks.

BTW, my Formula does not have a fuel shut-off valve and I had no problem with fuel draining into the module while working on this. If you have a shut-off valve, use it.

That's it!

there is also another filter below the cup that you are showing. it looks like a shallow round tray and you pull it out with needle nose pliers. they are not cheap. Jim

I saw that in there, like a strainer and thought it was permanent. Mine looked clean. Do they sell replacements or is it cleanable? Didn't see anything in the manual about it. Thanks!

usually you replace them. p.n. 35-892665

how much?

Good information. I agree that the secondary filter (35-892665) should be replaced also.

I learned this the hard way (snapped a bolt off in the module), clean the bolt threads and apply thread sealant before reinstalling the filter cap. Also, don't pull the filter out unless you have a new o-ring for the filter cap. The o-ring swells up slightly and may not reinstall properly.

Merc service bulletin on Gen III Cool-fuel diagnostics;

http://www.marinepartsman.com/Mercur...2004/EN_06.PDF

Gen 3 fuel filters
 

has any one found these parts somewhere where they don't cost an arm and a leg. Mercury sells a kit which has both the dic orin and paper cartrige but its about $65.00 for a set . I need two everytime