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Fuel Pump 101

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  • Fuel Pump 101

    Okay, I am starting this post to help educate ourselves and possibly get to the bottom of the MC fuel pump problem. I have included a gazillion pictures. So, please bear with me.

    Is there a problem with the MC fuel delivery system? I think so. An unofficial poll on another website showed that MC has a 4 to 1 failure rate compared with other ski/wakeboard boats. Visit the other boat manufacturers forums and type in "fuel pump" and you will get only a handful (if that many) results. Do the same search on this forum and you will be reading for hours. In an email reply to my questioning the problem, the representative said, "Federal Mogul did make a pump body change to help with recurring pump failures and high warranty claims." "Recurring pump failures" and "high warranty claims?" Sounds like a problem to me!

    MC did extend the warranty from one year to two for the fuel pump. And, they added a "warning" to the manual of NEW boats about running with less than 1/4 of a tank. Any sane person will tell you that this does not fix the problem. IMO, MC should of engineered a fix and done a 100% recall. It is the only fair thing to do for the 1,000's of people who paid top dollar for the best.

    Okay, so let me get started with the pictures. The pictures are more or less to help those who have never seen a fuel pump module in detail. The entire process of removing the module and taking it apart was a learning experience. I have posted quite a few times regarding this fuel pump issue and I have been wrong in some assumptions. But, I am learning.

    Well, here is the fuel pump module from the outside.
    NOTE: the 12 bolts that mount the pump to the tank should be torque to 49 inch pounds (thanks JimN for the info).

    Remove the 12 bolts, the vent hose, and the wiring harness and it comes out like this.

    I removed the fuel line to the motor with a special tool. This allows the module to come completely out.

    Remove the 3 screws on the metal sleeve and this is what you see on the inside.

    The fuel pump is held in by a plastic support at the bottom of the module. The smooth black fuel hose is quite rigid and in my module it was kinked (quite a bit IMO).

    Here is the underside of the top portion with the hose already removed. The clamp on this hose is a one-time usage clamp.
    Last edited by Team MC; 08-25-2012, 08:42 AM.
    Common sense is the least common of all the senses.

  • #2
    The round thing on the top of the module is the regulator. The pump sends fuel to the regulator at a certain pressure. The regulator decreases the pressure to match what the motor requires. This means that there is more fuel going to the regulator than is needed by the motor. Any excess fuel is squirt back into the tank.

    A clear view of the pump inside the module.

    Remove the 4 screws holding in the pump bracket and here is the pump (culprit?).

    Nice QC (quality control). Look at the rubber bushing. Geezus!
    Last edited by boofer; 08-11-2008, 01:22 AM.
    Common sense is the least common of all the senses.


    • #3
      The bottom of the module.

      The black hose on my pump was quite twisted and kinked. It is hard to see from this photo. But, my hose is kinked enough to reduce the allowable flow of fuel at least 30%.

      Add a little more bend and you get NO flow.

      The pump.

      The nomenclature on the pump is not a serial number or anything like that. It is a manufacturers number and cannot be crossreferenced (I tried).
      Common sense is the least common of all the senses.


      • #4
        Now here is the bottom of the module. It has a circular disk on the bottom.

        I am not sure why it is there. It is buoyant and has the 3 channels that you can see. When it is "up" the pump can draw fuel. When it is down fuel cannot be drawn by the pump.

        Here is a picture of the picture of the top of this disk. The small rubber tab in the middle goes into the small hole at the bottom of the module.

        Here is a side view of the small disk. This is actually from the new module and it is shaped differently than the old one. The old one does not have the 2 different diameters.
        Last edited by boofer; 08-11-2008, 01:24 AM.
        Common sense is the least common of all the senses.


        • #5
          The bottom of the module without the small disk.

          Now, some observations. The new module has a corrugated clear hose to the regulator.

          It retains its shape even when bent. But, somewhere on this board, I read a post (with pictures) from a new owner who had these types of hoses burst. I haven't the time to look it up.

          The small black bypass hose on the outside does not line up with the groove made for it. You can even see a mark where it should be. What is up with this? Piss poor QC in my book.

          I tested the small disk. It is buoyant. Almost like a piece of cork or wood.

          I was very curious about the filter and how quickly fuel will pass through it. I poured some gas in a pan and placed the filter in the gas. The filter filled up quickly. So, there is virtually no restriction to the flow of gas through this filter. I had originally thought that the 10 micron filter was too restrictive. Not true. The only problem (if you want to call it one) with the filter is that due to its shape, it cannot draw gas from lower than the bottom lip.

          A so so picture of the filter.
          Common sense is the least common of all the senses.


          • #6
            So, what is the problem with this design? I really do not know.

            1. Gas flows through the filter fine. No poblems here.

            2. I submerged the module with the small disk installed and it did take an inch or so of gas to "unplug" the hole (which leads to the pump). I would really like to know the purpose of this small disk. Problem? Possibly.

            3. The kinked fuel line to the regulator. It was definitely kinked more than it should be. It would be creating a fairly significant restriction to the flow from the pump. Would this "back" pressure harm the pump? I do believe that it does.

            4. The pump itself. I am almost certain that it is a poorly designed pump.

            In my reading, it appears that this rotary vane style pump had too small of tolerances and prone to failure. Read this from Carter. I would really like to know if GM issued a recall regarding these pumps. If so, then I think that we should get the same recall.

            I emailed MC and inquired about fuel pump failures. The first replay sent to me basically said that MC was not aware of any fuel pump problems. I replied with disagreement stating the unofficial poll I ran and the multitude of posts on their own website. Their reply stated that there was a design problem with the Carter pumps. It also said that they (MC) was working with 2 pump suppliers "to reduce the failure rates, and durability regarding low fuel situations." Apparently these 2 suppliers are Carter with their turbine style pumps and these Milinium pumps. I have asked if my new module contains one of the new pumps. I have not yet received a reply.

            I am upset that MC is not being more proactive with this situation. And, apparently the situation has been around for many years. I opted for MC over the other boats because I was willing to dig for the cash to have the best. I would not trade my boat for anything. But, I feel somewhat let down. Instead of getting the engineers off of their butts, MC has done what they can to skirt the issue.

            I am going to visit a Federated auto parts store hopefully this week. I went to 3 major auto parts stores and no one could get a cross referenced pump to replace the Carter one. The fellow I spoke to at Federated said he wanted to help me out. He has 18 years in the business and has had his own dealings with hard to find parts. As many of you might know, a call to Carter/Federal Mogul will get you nothing. MC has forbid them to give out any details/specs with regards to these fuel system modules.

            Okay, for now my brain is fried. I got 2 nasal douches out on the water today and my eyes are starting to hurt from looking at this computer screen. Please feel free to chime in. I will update as soon as I get by Federated and if I hear anything else from MC.
            Common sense is the least common of all the senses.


            • #7
              Fuel pump failures in later-model MasterCrafts are a pretty well-known phenomenon across the industry, and especially on this discussion forum. As a "victim" myself, I congratulate you on taking this on and appreciate the photographic step-by-step.

              I recall that GM had problems with their in-tank fuel pumps years ago, but I don't know the specific problem. I assume they use Carter pumps. I've owned GM trucks for many years and I've never heard of any recalls - at least not for any vehicle I've owned. I did have a trouble code on a previous truck that was read as failure to maintain pressure, and I was told it was due to a leaking internal valve. I tightened the gas cap, had them clear the code, and basically ignored the problem. It never recurred in 30,000 additional miles.

              Having dissected your fuel pump, what is your opinion of the oft-proposed mechanism of failure that fuel is only filtered below 1/4 tank and that if/when the filter plugs up, failure to pump cooling fuel is the reason for failure? Were you able to detect such an arrangement?
              '04 MariStar 230VRS/MCX


              • #8
                Great, job Boofer. I would have to say that a big part of the problem is the cheap plastic fuel line between the pump and module. This is very clear because, that seems to be the only thing they changed. WOW!!! That new line looks like a even bigger problem, waiting to happen, you would have thuaght they would have spent the extra money to do it right. When I replaced my hose I think it totaled approx. $3.00 bucks. Two hose clamps and about 8" of high preasure fuel line. I just made a small loop and connected it to fuel pump then regulator, and it has plenty of room to move with out kinking.

                I would suggest anyone told they need a new module as I was. They should first look at replacing that line. My MC dealer said the pump runs but no preasure, pumps bad $450.00. Sound familiar? Actually, I would replace that line before it causes you problems. I have a $740.00 tow bill, because that stupid little hose.

                After looking at the link to the GM fuel pump issue, it appears to me that the wireing harness is to blame not used on MC. If you close at the picture of the new GM module you will see a thick black fuel line in their module, HHHMMM very intersting.


                • #9
                  boofer, have you tested your old pump.


                  • #10
                    Outstanding post Boofer, thanks.
                    So what about this floating disk? Sounds like it is designed to only allow the pump to run if there is enough fuel to pick up? So is this mechanism failing, allowing the pump to run when the tank is empty, thus running dry and burning up?
                    2003 ProStar 209, 2 flags, 8 cup holders


                    • #11
                      Befor I ever had a fuel pump problem I had ran my boat on empty many times to the point were I actually ran out of gas at least three times. I actually had to put a gallon in just to get to the gas station. I have a short trip from my marinia and were I ride with a gas station on the way, so when I read all this buisness about not running under a 1/4 tank I was curious as to why that is.
                      Then I seen that it only applied to the newer MC's. After closer inspection, I noticed the new MC's only have one line from the module to the motor and mine has two, supply and return. When my boat is below a quarter tank and I turn my key on the pump primes the lines and dumps back in to the canister. While running it, it continues to fill the canister above the tank fuel level, because the pump rate is faster then the fuel will excape from the bottom of the filter. If you have ever pulled your model you see that the fuel dosen't exit the canister to quickly. This keeps my canister full which submerges the pump in fuel to keep it cool. Since In the new MC's you don't have a return line, I would suspect that the pump will continue to pull only the fuel through the filter, in low fuel situations, leaving the pump exposed, without the fuel in the canister it has a less cooling property's surrounding the pump, hense over heating. NOt sure but something someone should look in to.
                      Maybe someone with the singal line setup can try and run their boat at a half tank and pull their regulator off the top of the module to see if the canister is full. On my boat I was at a 1/4 tank and the fuel almost overflowed out of the whole on top the module (were the regulator was).


                      • #12
                        boofer...excellent post. Very nice pictures. I actually just replaced my fuel pump a few weeks ago (pump only). I can honestly say I wouldn't have been able to complete the job correctly with out the help from everyone on this board.
                        To some golfers, the greatest handicap is the ability to add correctly.


                        • #13
                          Keep up the good work!
                          04 197 TT LQ9 stargazer w/Z-Box
                          PB 2@35 off
                          96 Prostar 205 Lt1
                          93 Prostar 205 HO
                          81 Leaves and stripes(Can. edition)


                          • #14
                            Bigmac, I am pretty certain that the filter is not restricting the flow of fuel at any level. I poured gas into a pan to about 3 inches deep. I placed the filter in the pan and it immediately filled up with gas. I was expecting to see it trickle in, but that was not the case. The level of the gas inside the filter equaled the level of gas on the outside of the filter within milliseconds. So, the filter does not restrict fuel. By the way, this is the replacement filter I used on my old module only a few months ago prior to replacing the whole fuel module. The new module came with a new filter.

                            I am really puzzled though by this small black disk. I cannot see any useful purpose. I basically used the same pan of gas. I slowly sunk the bottom of the module in the pan of gas (without the pump so that I could see the gas). Gas would not populate the small area at the bottom of the module until the module was all the way in the gas. I cannot recall now if I had the filter attached. I do not think that it was attached since I was trying to see what effect this disk has on flow to the pump. Basically the disk floats. When there is sufficient gas to float it, it will unplug the hole allowing fuel to go to the pump. If it is not floating the hole is closed and fuel will not get to the pump. Plus, I would gander that the pump is able to somewhat pull this small "valve" open when it is running. But, that would make it a restriction. I cannot really say one way or the other what the purpose of this disk is. It would keep air out of the pump at low fuel levels. But, regardless, air in the pump or no fuel available to the pump equals overheat.

                            Bear, it is the fuel that goes through the pump that cools the pump. The fuel on the outside can aide in cooling, but the pump is designed to be actively cooled by the flow of fuel through the pump.

                            I am 50/50 with that "newer" fuel hose form the pump to the regulator. The old hose was definitely "substantial," but it did have the noticeable kink. The new hose is much stiffer than it looks. And it flexes well. I wonder if the corrugation helps reduce the flow to the regulator and eases the job of the regulator without creating any backpressure. But, one of the board members posted his problems with the dual pump (Milinium?) setup on his boat. Here is the link to his post.

                            Remember, the Carter brochure is just that; a brochure. The electrical issue (melted contacts) was experienced by a board member. He posted pictures just recently. But, I did learn that the pump was too restrictive and easily clogged which led to the high failure rate. I believe that I found this while researching the GM problems with the Carter pumps and the MC representative echoed the same information to me in the email. The pump was redesigned to be less restrictive and more tolerant of debris. When I say "debris," we are talking microscopic.

                            What I see for now is a poorly designed pump. It was replaced in GM motors. So, why not do it in ours? I am still awaiting a reply to my question as to whether or not my new module came with the newer turbine style pump. If not, then I must really question MC's policies. They apparently thought there was enough of a problem to use a different pump(s) on newer boats. If they are not actively trying to get these newer pumps in older boats (replacement modules with the newer pumps) then I must call foul.
                            Last edited by boofer; 08-11-2008, 03:21 PM.
                            Common sense is the least common of all the senses.


                            • #15
                              Kudos Boofer, great post !!!

                              I own a 2006 X-45 with an L-18 engine. Last week I had to change my fuel pump the second time (same happened last summer during a storm ). Let's say, I am somehow experienced replacing the fuel pump.

                              Because my MC is out of warranty, I tried to find out if I can get this tiny fuel pump somewhere without replacing the whole kit (and being charged with 600 EUR, roughly 900 USD).

                              I was lucky, the MEAT & DORIA 76201 is exactly the fuel pump I needed, bought in a standard car parts shop in SalÚ (Lake Garda, Italy) for small money. Obviously this pump is standard in Fiat automobiles.

                              So what about this floating disk? Sounds like it is designed to only allow the pump to run if there is enough fuel to pick up?
                              This "floating disk" is a valve, holding back fuel in the plastic container, even if the fuel tank is almost empty.

                              My analysis: both pumps has been burned due to lack of cooling or bad manufacturing quality. I never ever ran my boat below 1/4 tank. This "floating disk" valve might be the key for all problems. If this valve is not floating properly, the container reservoir will not be filled properly with enough fuel, the pump run out of fuel and cooling.