cool fuel 2 rant...

SrtThis

Member
Feb 20, 2019
74
Maryland
Boat Info
270 SE sundancer
Engines
7.4 MPI w/bravo III
ok this is just a rant about the entire cool fuel 2 system...

honestly could they have found a dumber location? unless you are about 5'5" tall and under 200lbs (so pretty much no boater ive ever meet) you cant get to it. really... who thought putting a fuel pump and regulator under the damn motor was a good idea? im a mechanical designer and i can honestly say if i would have brought up doing something like this up in a design review i would have been fired on the spot. i guess thats the difference between a designer who never works on anything and a designer who can design it... machine it.... assemble it... and service the unit.
2... what the hell is the actual point of it? if they are truly worried about fuel temps... put the damn fuel pump some where NOT under or next to the damn motor!

rant over
 
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I hear ya. I ended up replacing my cool fuel 3 module and ended up relocating it, might never have to mess with it again, but if i have to, it'll be easier.
 
That’s the whole problem with the inboard gas engines, in my opinion. They are gas engines designed for the automotive world, then some engineers get together and try to adapt them to use in water. And these designs never seem to be about longevity or at least “easy maintenance”. The added on parts that touch salt water all seem to have issues, raw water pumps, fuel pumps, risers, elbows, etc. maybe that’s the salt, and not the design, but my Yamaha 200 needed nothing (comparatively) for 14 years. Seems like the outboards in most cases) are just designed from the ground up to be in salt water.
 
That’s the whole problem with the inboard gas engines, in my opinion. They are gas engines designed for the automotive world, then some engineers get together and try to adapt them to use in water. And these designs never seem to be about longevity or at least “easy maintenance”. The added on parts that touch salt water all seem to have issues, raw water pumps, fuel pumps, risers, elbows, etc. maybe that’s the salt, and not the design, but my Yamaha 200 needed nothing (comparatively) for 14 years. Seems like the outboards in most cases) are just designed from the ground up to be in salt water.
i can definitely see something like this happening... guess for me the inboard vs outboard was more of a not wanting to learn ANOTHER type of engines. i spend too much time working with 2K+ hp drag cars and wanting to learn anything else is just going to take too much time for me. a BBC i figured would be "simple" for me... guess that is actually a lie LOL
 
I bet I can get my CF2 out quicker than you could get the fuel pump out of your truck. Doesn't get much easier than a single engine boat Think about getting one off your stbd engine with twins.
 
I bet I can get my CF2 out quicker than you could get the fuel pump out of your truck. Doesn't get much easier than a single engine boat Think about getting one off your stbd engine with twins.

you would lose that bet... ive had mustang tanks down and back in swapping pumps out in under 30 minutes lol
 
If you didn't already buy the pump the Airtex E11004 is a good replacement for under a $100.
 
In another 20 years ? Hope you did your regulator while you were there and used a good brand of heat paste.;)
 
In another 20 years ? Hope you did your regulator while you were there and used a good brand of heat paste.;)
haha i used the whole quicksilver fuel cooler kit... new pump, regulator, cooler, o rings, and new paste. cleaned up all the fittings and plates with scotchbrite. kinda wish i would have ordered new water lines also
 
So it was financially panful as well then. LOL I would have been more concerned about the rubber fuel lines that are 20 years old.
 
My 99 260 with the 7.4 is new to me but have decided the placement of the cool fuel and filter all suck!!!
so basically they try to cool the return line all one or two inches of it then pass the fuel lines to and from the filter right next to the oil pan .... theres close to 190 degrees soaking into your fuel lines... then the line from the cool fuel to the fuel rail has an insulating sleeve on it that was painted black... black soaks in the heat..that insulation is silverish foil like material when new.
So I moved my fuel filter away from the block, took cover off the cool fuel for air flow, also removed covers off the top of motor and fuel filter.
I then focused on the venting... starboard hoses removed as they actually reduce the air flow into engine compartment.
then added a second inline blower and re positioned the hoses at the portside vent so they actually exhaust outside. I also moved my "spark arrestor" to the starboard vent as close as I could so the motor inhales fresh outside air. I can now feel the air getting pulled into starboard vent when blowers are on and engine gets nice cool air.
fuel lines aren't sitting next to 190 degree oil pan and all is great! I should'nt have anymore heat related issues.
 
You are making me wonder about moving the CF2 assemblies to the STBD side of the engines, before the Trans oil cooler, about midway up the engine, or somehow mounted to the transmission motor mount. I haven't seriously looked at this yet, but hmm (insert chin scratch here). 6 connections. Raw water in, raw water out; fuel in to high pump, fuel out back to the separator, vacuum hose to the intake plenum, and electrical connector for the pump. Why not?
 
You are making me wonder about moving the CF2 assemblies to the STBD side of the engines, before the Trans oil cooler, about midway up the engine, or somehow mounted to the transmission motor mount. I haven't seriously looked at this yet, but hmm (insert chin scratch here). 6 connections. Raw water in, raw water out; fuel in to high pump, fuel out back to the separator, vacuum hose to the intake plenum, and electrical connector for the pump. Why not?
its pretty tight there also... got the starter and all that BS there.
 
A couple side notes...

Mercruiser has stated that the reason for locating the CF module where it is is to better control heat. Mounting it low helps control heat. Also, that plastic box that surrounds it? Believe it or not, that supposedly keeps the internal temp of the CF unit about 15* lower. But many have found that running without it still works just fine. I wouldn't mess with what the engineers have found to work, and work well, for thousands and thousands of boaters.

Now, could you move it somewhere else? Sure. Could it be a better place? Sure. Will you see any real benefit? Doubtful. But you can't blame Merc for the location - they sell the motor as a package deal and it needs to be as close to a "drop-in" as possible. It would be up to the manufacturer's to mess with the CF unit, otherwise.
 
Last edited:
If the concern is vapor lock, plumbing the fuel pump return line back to the fuel tank is the fix.
 
You are making me wonder about moving the CF2 assemblies to the STBD side of the engines, before the Trans oil cooler, about midway up the engine, or somehow mounted to the transmission motor mount. I haven't seriously looked at this yet, but hmm (insert chin scratch here). 6 connections. Raw water in, raw water out; fuel in to high pump, fuel out back to the separator, vacuum hose to the intake plenum, and electrical connector for the pump. Why not?

So I ran mine Saturday after moving the fuel filter and covers from top of engine and cool fuel 2 .... I hooked the seawater hoses back up and ran all day Saturday with no problems...
Between that and relocating my air intake (spark arrestor) to the starboard vent area (also opened that up a little where the two 4 inch holes for the hoses used to be.... the boat ran cooler. I would let it idle for 2-3 minutes after stopping and the temp would drop a few degrees on the gauge....
that and two blowers that run while engine is running and my engine compartment stays much cooler
its pretty tight there also... got the starter and all that BS there.
A couple side notes...

Mercruiser has stated that the reason for locating the CF module where it is is to better control heat. Mounting it low helps control heat. Also, that plastic box that surrounds it? Believe it or not, that supposedly keeps the internal temp of the CF unit about 15* lower. But many have found that running without it still works just fine. I wouldn't mess with what the engineers have found to work, and work well, for thousands and thousands of boaters.

Now, could you move it somewhere else? Sure. Could it be a better place? Sure. Will you see any real benefit? Doubtful. But you can't blame Merc for the location - they sell the motor as a package deal and it needs to be as close to a "drop-in" as possible. It would be up to the manufacturer's to mess with the CF unit, otherwise.
A couple side notes...

Mercruiser has stated that the reason for locating the CF module where it is is to better control heat. Mounting it low helps control heat. Also, that plastic box that surrounds it? Believe it or not, that supposedly keeps the internal temp of the CF unit about 15* lower. But many have found that running without it still works just fine. I wouldn't mess with what the engineers have found to work, and work well, for thousands and thousands of boaters.

Now, could you move it somewhere else? Sure. Could it be a better place? Sure. Will you see any real benefit? Doubtful. But you can't blame Merc for the location - they sell the motor as a package deal and it needs to be as close to a "drop-in" as possible. It would be up to the manufacturer's to mess with the CF unit, otherwise.

I u DeRay and why they engineered it that way ... like you said a package deal.
With that said it is located right next to the hot oil pan... the plastic cover once the engine is hot, soaks in that heat and holds it in.... what I have done with mine works well... the heat issues isn’t one problem... it is a culmination of poorly executed good ideas!
Like the fuel coolers fuel ports are smaller than the fuelLines to and from it!!
Once I get mine out ( it’s getting corroded pretty bad) I’m going to cut it up and see the difference. I also plan to do a temp bypass and log engine engine performance and economy before and after.. I know with mods I’ve made so far my boat runs better, smoother, quieter and uses less fuel
 

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With that said it is located right next to the hot oil pan... the plastic cover once the engine is hot, soaks in that heat and holds it in.
Yes, but... ;) The box also helps to make an "air buffer" of sorts. With the constant supply of 70* water flowing through the hose, the box helps to keep the interior of the box cooler. It sort of "counters" the heat transfer from the engine. As you may notice, even the inlet hose up at the t-stat housing stays cool. If the water wasn't moving, that would be different - but there is a constant supply to keep things cooler. Granted, it's not a perfect system - but it is effective.

Besides, overheating (with these engines) is rarely a problem - unless there's a different issue, of course. But under normal circumstances overheating or hot fuel issues are pretty much non-existent - especially with fuel injected engines.

I'm certainly not saying don't try and improve the system - far from it. But for most endusers, the cost in parts and labor to do this is far greater than the minimal return that they might see in fuel economy.

There would have to documented proof - likely for hundreds of hours of use (both ways) for it to a realistic comparison - there are just too many variables, otherwise.

As far as engine temps go - personally, I would want to keep the engine temp higher as it's more efficient there. And given these engines only run in the 170* range to begin with, they are by no means "pushing the envelope".

But all that said - if you can make a better mousetrap for yourself, go for it! :)
 
Yes, but... ;) The box also helps to make an "air buffer" of sorts. With the constant supply of 70* water flowing through the hose, the box helps to keep the interior of the box cooler. It sort of "counters" the heat transfer from the engine. As you may notice, even the inlet hose up at the t-stat housing stays cool. If the water wasn't moving, that would be different - but there is a constant supply to keep things cooler. Granted, it's not a perfect system - but it is effective.

Besides, overheating (with these engines) is rarely a problem - unless there's a different issue, of course. But under normal circumstances overheating or hot fuel issues are pretty much non-existent - especially with fuel injected engines.

I'm certainly not saying don't try and improve the system - far from it. But for most endusers, the cost in parts and labor to do this is far greater than the minimal return that they might see in fuel economy.

There would have to documented proof - likely for hundreds of hours of use (both ways) for it to a realistic comparison - there are just too many variables, otherwise.

As far as engine temps go - personally, I would want to keep the engine temp higher as it's more efficient there. And given these engines only run in the 170* range to begin with, they are by no means "pushing the envelope".

But all that said - if you can make a better mousetrap for yourself, go for it! :)
Well being in a black box and heat goes where it’s cooler I chose to remove the cover and it works.
Fuel injected engines typically run at temps around 210. But that’s in cars that have much better ventilation.
My modes cost me around 40 bucks.
My fuel filter is much easier to get to and change and my engine now inhales the much cooler outside air as supposed to factory placement right next to exhaust risers. The cool fuel 2 is a great idea but the fuel flow is restricted and at 3/4 throttle that 454 shouldn’t have any kind bog or hesitation... it’s not bad and to people that don’t know, well no biggie. But with what I have done I now cruise at 30-34 mph at 3000-3200 rpm
Instead of 3500-3800 @ 23-28 mph.
Air flow being my biggest improvement
Bigger opening on incoming side and adding a second inline blower and having short exhaust vent hose from blower to exit on port side.
 

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