Gen III Fuel Module Issues

D

duke618

New Member
Apr 24, 2012
3
delaware
Boat Info
2006 34 sundancer
Engines
8.1S v drives
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Re: Mercruiser Gen III Cool Fuel Module

I have a 2006 34 sundancer w 8.1s. Had same issue w paint. They found it in
the regulators, fuel pumps, module, filters and injector screens totally clogged the entire
system. Apparently came from the fuel module. They appear to be painted on inside
and the fuel deteriorated it. All at a cost for both motors of over 4k.
Entire system was flushed and replaced. Mecruiser did have service bulletin but not for this. Anyone else with this issue
reason. They changed the water intakes to barbed and threaded. In my marina
alone there are 7 other boats with exactly the same issue​
 
duke618 said:
icon1.png
Re: Mercruiser Gen III Cool Fuel Module
I have a 2006 34 sundancer w 8.1s. Had same issue w paint. They found it in
the regulators, fuel pumps, module, filters and injector screens totally clogged the entire
system. Apparently came from the fuel module. They appear to be painted on inside
and the fuel deteriorated it. All at a cost for both motors of over 4k.
Entire system was flushed and replaced. Mecruiser did have service bulletin but not for this. Anyone else with this issue
reason. They changed the water intakes to barbed and threaded. In my marina
alone there are 7 other boats with exactly the same issue​
Click to expand...
Yes - i replaced both of mine - the paint flakes off the fuel pump cover and clogs the regulator - in my case i did not have to go any further - some have said the ethenol in the fuel has caused this problem
 
What years would this affect?
 
Ididntdoit said:
I believe its '05 and up
Click to expand...

Yes I believe it's 2005 and up. What we can't figure out is why in the world would anything that comes in contact with gas would have a painted surface. Thankfully I had a passport warranty and most was covered. Since that's the case it must be more widespread than just a handful of issues. Ethanol is a caustic liquid and there is no getting away from it.
 
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Did you actually confirm the inside of the Cool Fuel Unit is painted and E10 caused the paint to come off?

I started wondering why the filter wouldn't have caught the paint particles so I went back to an old posting I created two years ago http://clubsearay.com/showthread.ph...l-unit-compete-with-pictures?highlight=filter As you look thru that thread you will come across this diagram that Dennis (Lazy Daze) posted:

1872.jpg


As you can see the fuel goes thru the filter first (reference point A) and then it goes thru the rest of the fuel body before it exits to the fuel rail (reference point F). So if the inside of the module is indeed painted then it is easy to see how it could pick up paint particles if they are coming off.

Just the same it would be nice to have a Mercury Tech confirm this really is a problem. I have about 450 hours on my motor and no problems like this have surfaced yet for me but I have never put E10 in my tank.

Dave
 
Yes, I have confirmed it - as I said it is the bolt on cover (over the fuel pumps) that was the problem on mine. the housings themselves were not flaking but one of mine had corroded to the point of a small internal leak! I caught it just in time! The corrosion (and ****ty water fittings) are a problem even on closed cooling boats as these units always use raw water to keep the fuel cool enough.

I started looking for a problem because I had a "rich" condition and slightley higher fuel burn in one motor - I found the fuel pressure was higher than normal and traced it to the clogged regulator - from there I found the corrosion in the housing and flaking paint in the cover - I shudder to think of the cost if I had to pay a tech to properly diagnose and fix this problem.....glad I'm able to diagnose and fix things myself
 
Ididntdoit said:
Yes, I have confirmed it - as I said it is the bolt on cover (over the fuel pumps) that was the problem on mine. the housings themselves were not flaking but one of mine had corroded to the point of a small internal leak! I caught it just in time! The corrosion (and ****ty water fittings) are a problem even on closed cooling boats as these units always use raw water to keep the fuel cool enough.

I started looking for a problem because I had a "rich" condition and slightley higher fuel burn in one motor - I found the fuel pressure was higher than normal and traced it to the clogged regulator - from there I found the corrosion in the housing and flaking paint in the cover - I shudder to think of the cost if I had to pay a tech to properly diagnose and fix this problem.....glad I'm able to diagnose and fix things myself
Click to expand...


I am posting these pictures of the top of the module. You are looking at where the regulator goes and you can plainly see the paint that has peeled off and ready to go into the rail and then to the injector screens. Which of course will clog the injector and then prohibit the cylinder from getting fuel etc etc etc

photo(1).JPG
 
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So is the fix to remove and clean the regulator or replace the regulator?

So far I have not had any problems, but I would like to catch and fix any issues before bigger problems start. Living in New Jersey, there is no place to buy fuel that does not have ethanol, so I am especially concerned.
 
Vince_nj1 said:
So is the fix to remove and clean the regulator or replace the regulator?

So far I have not had any problems, but I would like to catch and fix any issues before bigger problems start. Living in New Jersey, there is no place to buy fuel that does not have ethanol, so I am especially concerned.
Click to expand...
Do yourself a favor - next time you need to do an impellar, remove the cool fuel unit first - it will make the impellar replacement much easier - once you have the module off remove the top cover and clean it out - chances are good that its already flaking - soak it in laquer thinner and blow it out real good to get all the paint out - some tips - make sure you have a replacement fuel line o-ring, you need the actual merc replacement ones - if you still have the "stock" plastic nipple water fittings reattaching them is hit or miss - If your housing is still good and you don't want to upgrade to the new design, someone on e-bay sells stainless nipples that use the otherwise factory retaining hardware - If you choose to replace the housings you DO NOT need the hose kits they try to sell you - there is enough "slack" in the hoses if you cut off only what you have to to remove the fittings.....
 
The dealer replaced mine under warranty last fall when they were winterizing,I was talking to one of the mechanics working on a 260 a few slips from my boat today,he just finished replacing one of these and showed me the paint and bad hose connections, around $1400...
 
Hi Guys, I may have posted this in the wrong thread previously, but hey they are both dealing with the inherent inadequacies of the very lamentable design of the MERCRUISER GEN III fuel cooler. Its been very interesting reading all the forums around the world all about inexcusable problems with the Mercruiser and their Gen III fuel cooler.
I have the high fuel pressure problem with the Gen 3 fuel cooler on my Mercruiser 2005 5.0L MPI bravo3, some 85-90psi at the rail, I am waiting for the fuel regulator which is in the process of being shipped from the USA now, apparently they do not exist over here in the UK.

The so called highly trained Mercruiser mechanics over here do not seem to have heard of this problem but hey when you go on line its all there loads of info in various forums. After 5 visits consisting of 12 hours Changing the small muffler filter (no different) then the IAC Valve (£190, still no different so put old one back) then the plugs and leads (oh yes - no different) now agreeing with me that it is running rich very rich loads of carbon out the back in the exhaust the new plugs they fitted carboned up in the first 5minute run. they then fitter an old regulator valve (same old - no different of course it could have been faulty) he then piggy backed another Gen3 cooler and apparently it worked but they never tried using the regulator valve from that unit.
They have now told me that I need a new cooler £800-1000, cant see it my self and I have no leaks at present, I find it hard to believe that the pumps are faulty when you are getting over pressure if they fault you normally get under or no pressure. I think it is this valve which I cant obtain in the UK. I was also thinking of getting a new cover and if necessary a new block, but I will get it from the states and ship it.
Sorry about the sarcasm just a bit frustrated, especially when you think you are paying for professionals to sort your problems and they seem clueless so much for Mercruiser training.

Chillaxin, You mentioned you had produced some stainless hose to block termination do you have a pair left? if so how can i purchase a pair from you?
 
My problem started with a burnt relay and wire housing. The fuel pump was clogged with paint and was straining to get enough fuel to meet the pressure needed. This is what the inside of my Cool Fuel III looked like. Both fuel pumps worked, but they intake screen on the bottom of the fuel pump was clogged with paint. Unfortunately, I didn't get a chance to take a picture of the fuel pump screen, because my neighbor scraped it off when I went to get my camera. However, you can see that the inside of the housing has lost most of the paint. I poured the fuel through a coffee filter and you can see the paint that came out. I did the repairs myself, so I am "only" out $2200.00. To make matters worse, the "redesigned" Cool Fuel III fixes the probelm with the water hose connections and adds a blue drain plug to winterize the unit, but THEY STILL HAVE PAINT ON THE INSIDE OF THE HOUSING!!!

Mercruiser should be sued for this crap.


P1050196-1.jpg
P1050199.jpg

P1050194-1.jpg
 
kj-GB said:
The so called highly trained Mercruiser mechanics over here do not seem to have heard of this problem but hey when you go on line its all there loads of info in various forums. After 5 visits consisting of 12 hours Changing the small muffler filter (no different) then the IAC Valve (£190, still no different so put old one back) then the plugs and leads (oh yes - no different) now agreeing with me that it is running rich very rich loads of carbon out the back in the exhaust the new plugs they fitted carboned up in the first 5minute run. they then fitter an old regulator valve (same old - no different of course it could have been faulty) he then piggy backed another Gen3 cooler and apparently it worked but they never tried using the regulator valve from that unit.
They have now told me that I need a new cooler £800-1000, cant see it my self and I have no leaks at present, I find it hard to believe that the pumps are faulty when you are getting over pressure if they fault you normally get under or no pressure. I think it is this valve which I cant obtain in the UK. I was also thinking of getting a new cover and if necessary a new block, but I will get it from the states and ship it.
Click to expand...

This problem has been documented multiple times here. If you are lucky the paint has not yet fouled the fuel rail and injectors. Doubtful since this problem is one that happens over a long period of run time and engine performance degrades slowly. By the time the problem is properly diagnosed the paint has moved downstream of the fuel unit. Changing the entire fuel module makes the most sense because of another known issue, the high rate of raw water fitting leaks! Oopps, hope I didn't spoil the surprise ending...
 
How does one figure out if they have the Gen II or Gen III cool fuel? I seem to be in the right year range and motor listed, but I dont recognize the picture of the Gen III module as something I've seen on my engines. Hoping I have the II, but not sure what I'm looking for.
 
JimFromMD said:
How does one figure out if they have the Gen II or Gen III cool fuel? I seem to be in the right year range and motor listed, but I dont recognize the picture of the Gen III module as something I've seen on my engines. Hoping I have the II, but not sure what I'm looking for.
Click to expand...
It was phased in during the 2005 model year best I can tell. My boat is an early production 2005 model (5.0MPI) and I have it. If you have two "oil filter" style and inline filters you have Gen2. Otherwise you have Gen 3. The Module is mounted just to the left of the raw water pump (when looking at engine from front).Has anyone has these issues that never used ethanol gas? I seem to recall maybe another thread someone said the ethanol gas breaks down the paint.
 
I'm not so sure about the E10 thing, how many thousands of cool fuel III trailer boats are used with nothing but gas station E10 and you dont see them dropping like flies.

How many of these paint falling off fuel modules get winterized?

Maybe its E10 being used in the winterizing 'cocktail' plus the combination of sta-bil and certain types of 2 cycle oil used then sitting for 5-6 months thats eating the paint. Maybe its just certain brands of fuel with extra detergents/cleaners attacking the paint. I replaced my CFIII housing (water fitting issues) and the paint inside looked fine, only had a 200 hours on it but its five years old.

The new housing was painted (well coated most likely) inside as well, wouldnt be so bad if the filter caught it, but once that stuff gets in the rail/injectors you can do even more damage if a cylinder or two starts running lean from a clogged injector.
 
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