Jump to content
Sign in to follow this  
ColdOne

Gen II cool fuel module vs Gen III cool fuel module

Recommended Posts

When I ordered my replacement module this year on Amazon I merely went to recently purchased items and ordered what I bought last year or so I thought. Today I received my order and guess what I got a Gen III module instead of a Gen II. So my question is what is the difference and can I use the Gen III module in the Gen II housing?

Share this post


Link to post
Share on other sites
4 hours ago, ColdOne said:

When I ordered my replacement module this year on Amazon I merely went to recently purchased items and ordered what I bought last year or so I thought. Today I received my order and guess what I got a Gen III module instead of a Gen II. So my question is what is the difference and can I use the Gen III module in the Gen II housing?

I think you need to start by being VERY specific about what you have.  You say you purchased a Gen 3 module, but are asking if it will work with a Gen 3 housing.  The module itself is the entire housing, pumps, filter, regulator, etc.  I'm totally confused by your question.

If you did some forum searching you'll see i just replaced a Gen 3 module.  There are certainly some differences that may require a new seawater hose because the connections to the Gen 3 are different.  Otherwise, it's simply a bolt on unit.

So let's start with that.  Photos will help too.

Share this post


Link to post
Share on other sites

Personally?  Unless there's a bulletin from Mercury that says Gen II cool fuel modules can and are being replaced by the Gen III for your engine serial #, I wouldn't use it.

It's probably the same high and low pressure pumps and filters and restrictors etc., and I'm guessing it's probably fine and the only differences are no paint inside and improved cooling passages and little things like that, but you never know.  

If the pumps are different in any kind of way, then you'll be getting the wrong fuel flow to the engine and that's probably not a good thing.  Just call Mercury and ask them.

Share this post


Link to post
Share on other sites
2 hours ago, Hatem said:

Personally?  Unless there's a bulletin from Mercury that says Gen II cool fuel modules can and are being replaced by the Gen III for your engine serial #, I wouldn't use it.

It's probably the same high and low pressure pumps and filters and restrictors etc., and I'm guessing it's probably fine and the only differences are no paint inside and improved cooling passages and little things like that, but you never know.  

If the pumps are different in any kind of way, then you'll be getting the wrong fuel flow to the engine and that's probably not a good thing.  Just call Mercury and ask them.

Agreed!  It's easy to call Mercury and ask.  He's got a 2008 boat (same as mine) so I think he may be calling it the wrong thing.  For the life of me I cannot find a Gen II cool fuel module on Amazon at all.  And he says he bought the same thing as last year.  These things are not annual items.  I really think we're talking about two different things.  Part numbers will help immensely.  I even looked at the parts guide for that year model 496 Mag and it shows a Gen III module.

Share this post


Link to post
Share on other sites

I think cool fuel 2 ended in 04. From what I have found out is the 05 to 07 cool fuel 3s were the problem ones with the paint. 

Share this post


Link to post
Share on other sites

Stupid really as they never intended to paint the housing interiors. If you look closely, you can see that the interior coating was just over spray from when the cast aluminum tanks were top painted. When I do service, I use 2+2 Gum Cutter carb cleaner on the insides as it melts that paint instantly. It seems like it all depends on which brand of fuel and/or which additive you are using as to whether or not the stuff turns to goo. I always find accumulated crud under the pressure control valve too. Strip them clean, re-install the old pumps, new filter base screen and element, and refill with fresh fuel before installation. I also replace the pump plate hold down bolts with studs and nuts as the heli-coils that are installed into the aluminum housing from the factory tend to grab the bolts and it's not uncommon to have one or two snap off. Stainless studs lock-tite into the housing, with self locking poly nuts. Also, check the water passage as they tend to be plugged at the inlet. Volvo was the first to discover the paint issue and got away from these types systems pretty quickly. Merc seems to like them as they do tend to help with high pressure fuel pump longevity. I say if you have a cool fuel module, remove it, dissemble it, and strip the interior coating.  W

Share this post


Link to post
Share on other sites
1 hour ago, Wingnut said:

Stupid really as they never intended to paint the housing interiors. If you look closely, you can see that the interior coating was just over spray from when the cast aluminum tanks were top painted. When I do service, I use 2+2 Gum Cutter carb cleaner on the insides as it melts that paint instantly. It seems like it all depends on which brand of fuel and/or which additive you are using as to whether or not the stuff turns to goo. I always find accumulated crud under the pressure control valve too. Strip them clean, re-install the old pumps, new filter base screen and element, and refill with fresh fuel before installation. I also replace the pump plate hold down bolts with studs and nuts as the heli-coils that are installed into the aluminum housing from the factory tend to grab the bolts and it's not uncommon to have one or two snap off. Stainless studs lock-tite into the housing, with self locking poly nuts. Also, check the water passage as they tend to be plugged at the inlet. Volvo was the first to discover the paint issue and got away from these types systems pretty quickly. Merc seems to like them as they do tend to help with high pressure fuel pump longevity. I say if you have a cool fuel module, remove it, dissemble it, and strip the interior coating.  W

Wingnut, was I right about the years? I have found several different year spans on the net, what I posted above seemed to be the most consistent.

Share this post


Link to post
Share on other sites
8 minutes ago, tomnjo said:

I say if you have a cool fuel module, remove it, dissemble it, and strip the interior coating.  W

Yes. The same can be done with the Volvo Penta’s as well. Volvo’s were not over-sprayed though; fully coated by design. So, it takes a bit more effort to remove and clean, but they clean up great.

Share this post


Link to post
Share on other sites
22 hours ago, TexasPilot71 said:

Agreed!  It's easy to call Mercury and ask.  He's got a 2008 boat (same as mine) so I think he may be calling it the wrong thing.  For the life of me I cannot find a Gen II cool fuel module on Amazon at all.  And he says he bought the same thing as last year.  These things are not annual items.  I really think we're talking about two different things.  Part numbers will help immensely.  I even looked at the parts guide for that year model 496 Mag and it shows a Gen III module.

I hope he's not buying a cool fuel module every year! lol.  The way he worded it sounded like he bought one last year also.  I think he probably meant he just went into his same account where he had bought stuff from last year.  Sounds like he should be fine with the Gen III.

@ColdOne, would like to know why you're replacing the old one?  Did one or both of the pumps fail? 

Share this post


Link to post
Share on other sites
21 hours ago, tomnjo said:

Wingnut, was I right about the years? I have found several different year spans on the net, what I posted above seemed to be the most consistent.

You have to go by serial number, then look at the OEM Merc parts website and that will get you to the right part number. Most of the differences were how the raw water lines connected.

https://www.mercruiserparts.com/496-mag-base-model-1a066166-thru-1a3

 

Share this post


Link to post
Share on other sites

All - sorry I have been AFK for the last week or so and the Forum stopped working on my cell. I need to figure that one out yet. Anyways I want to thank all of you for your comments / suggestions.

When I received my Gen III filter for whatever reason I was sure I had a Gen II Cool Fuel assembly in my boat, I blame it on chemo brain. But after doing some research I verified I do have Gen III housing in my boat as TomnJo so astutely pointed out.

The boat comes out of storage on the 23rd and I will be sure not to rely on my memory and will verify everything  as I get ready to put her in the water as I don't want to mess anything up! :D

Share this post


Link to post
Share on other sites
41 minutes ago, ColdOne said:

All - sorry I have been AFK for the last week or so and the Forum stopped working on my cell. I need to figure that one out yet. Anyways I want to thank all of you for your comments / suggestions.

When I received my Gen III filter for whatever reason I was sure I had a Gen II Cool Fuel assembly in my boat, I blame it on chemo brain. But after doing some research I verified I do have Gen III housing in my boat as TomnJo so astutely pointed out.

The boat comes out of storage on the 23rd and I will be sure not to rely on my memory and will verify everything  as I get ready to put her in the water as I don't want to mess anything up! :D

Ahhhhhhhhh.....so it's the filter you're replacing annually.  Haha...that makes much more sense.  Sounds like you're in good shape.  Best of luck with your treatments too!

Share this post


Link to post
Share on other sites

I'm finding more and more of the water ports plugged solid on the earlier cool fuel modules. Have not seen failed fuel pumps yet, but it's a wonder they don't freeze and brake in winter as the water does not drain properly. Per attachment, if your hoses are affixed in this manner, it may be worth a look.  W

 

https://www.marinepartsplus.com/catalog/mercruiser/serialize(value)/496_MAG_H.O._Model/881784004/12826-50

Share this post


Link to post
Share on other sites
9 minutes ago, Wingnut said:

Have not seen failed fuel pumps yet, but it's a wonder they don't freeze and brake in winter as the water does not drain properly.

Makes me feel a lot better about the way I was taught how to properly winterize my 8.1VP by my mechanic buddy.  Run the antifreeze through muffs as engine is running, then crank the throttle up to 1500 RPMs for about 30 seconds, bring RPMs down to idle for 30 seconds then back up to 2000 RPMs for another 30 seconds and all you have then is pure antifreeze coming out the outdrive, meaning all sitting water has been pushed out and replaced with antifreeze.  Beats the heck out of draining from plugs and just filling hoses and things like that.  This way, you literally push ALL the water out of ALL existing cooling passages.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×