Replacing Cool Fuel III

Just to throw this out there but why cant a trans cooler be used to just cool the fuel. fitting are threaded not barbed.
uses 1 1/4 inch hose and just mount the pump in a convenient location
 
My paint was pealing in the pressure regulator area only, big time, none anywhere else. Merc wants crazy money for these parts as well, and admits they're no better than the original, except for the pipe threaded nipples. Said there working on an anodized cover. I'm just gonna bead blast my cover and the pump well clean, and see what happens, my fuel burn tipped me off to what was going on.
 
Most EFI systems, including this one, are not returnless. That is, fuel is pumped to the fuel rails under pressure, and the injectors are fed from the rail. A fuel pressure regulator is mounted on the rail, and maintains rail pressure by returning unused fuel back to the CF3, where it is cooled and mixed with fresh fuel from the tank. As you open the throttle, more and more fuel passes through the injectors, and less is returned to the CF3. So, a simple cooler, like a trans cooler, does not allow for this return flow.

A diesel operates much the same way, but the fuel is returned to the tank, not a cooling unit. And, many of them do have a simple cooler, like a trans cooler, to cool the fuel. The CF3 also serves the purpose, after any maintenance is performed on the fuel system, of purging air from the fuel system, via this return system. Otherwise, you'd have to crank and crank the engine until the air bled out through the injectors, before the engine would start.

Dale
 
Why don't they put the pump in the gas tank where it belongs. The lower module is available for $450. $550 with cover. regulator is $175, pumps are about 200 each. And the way it sits wont last any longer than the 1 you got. I'm all about a low dollar fix.
 
Wow, lot's of activity on this thread tonight!

Scof, be careful with bead blasting. I was involved in an engine development protocol with some turbocharged corvette engines years ago, and we had problems with excessive leakdown, on engines with very few miles on them. We finally chased the problem down to a cast aluminum timing cover that had been bead blasted internally. After the engine was temperature cycled, fine bits of the blast media, which had impinged into the aluminum, were "popping out" of the casting, and circulating through the engine in the oil. If you bead blast the CF3, you may wind up with very fine media residue in your injectors.

To play it safe, just chemically strip the cover and interior, and be done with it.

Dale
 
I don't know about that one. CF3 has 1 feed line in and 1 pressure line out. The FPR on the cf3 makes the pressure, the FPR on the rail eliminates the pulse.
 
Hang on - I may have crossed that one with an older CF unit!

Dale
 
Interesting about the bead blasting, thanks for the tip. Another thing about the regulator on the rail, it's got the large feed line going to it and a smaller line leaving it , like a return, but I haven't tracked it down to see where it goes. It was a Merc tech that said its only purpose was to eliminate pulse
 
I have to do some digging - I thought I had an earlier Merc parts manual at my fingertips, but I can't lay my hands on it. If I recall, you are right, and it was an earlier design CF unit with a return line.

Dale
 
So Dale, is masterfabing your business or your hobby? No one in my area for a go to guy with talent
 
It's a side business now, mainly focused on custom fabrication, welding, and machining.

Dale
 
I could swear you could buy the thing without the pump and the filter - something like $450 (?)
 
A HA! Found it.

Part # 864650A14

Item 1 in the diagram below. Follow this LINK $427.00

44814.png
 
OK, I found it. An earlier version of Mercruiser's EFI system, like on the late 90s 502 engine (8.2L) had a return line, external regulator, etc. Sorry for the misinformation. The CF3 internalizes this flow. I blame Ron......

Dale
 
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Back on the original post there's a picture with laptop showing engine data. Did I miss how that was done? Could you explain how you got that data?
 
Great Post! As I recall based on prior discussion, there seemed to be some connection between ethanol gas usage and the breakdown of the paint so that may be why your was not affected?

The big question is, was the new CF3 module painted inside as well or have they abandoned that process which seems like was a huge mistake to begin with.
 
According to the people that answer mercs customer support line, nothing except the fittings have been changed. I have called several times recently and have got various answers to the same paint question. 1 fellow said the module was powder coated and the cover painted, which is in line with what I'm seeing as far as the flaking paint. The coating on my module and the bottom of the cover are rock solid with no sign of anything coming off. The area where the FPR sits and passages coming and going are completely coming off. Another tech told me it's all paint and no powder coat.
 
I have heard that the interior is painted even in the new models. This was a Long Island boat from original purchase through the 2012 season. The entire tri-state area (NY,NJ, CT) has had E10 since around 2007/2008, which is when these engines were installed. SO the boat has known nothing but E10.

My marina is in brackish to fresh water (depending on the time of year). So we get "flushed" every time we return to the slip. We pulled elbows on a friend's 2001 Maxum after 10 seasons and they looked new. His boat was in my marina that entire 10 year period. I don't know if this corrosion is related to salinity of water (electrolysis). Maybe there should be an anode in these CF units (??)
 
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