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'87 PS 190 351 Carb Rebuild

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  • '87 PS 190 351 Carb Rebuild

    Folks,

    A brief writeup. Carb appeared to be original to the boat, and with relatively low hours - 650hrs, I decided on a rebuild versus a replacement.

    The symptoms weren't severe, but I had some hesitation and stalling after idling for extended periods, and the transition was a little... just not crisp.

    I figured I would take it apart, give it a good cleaning, and see what happened.





    Hey, that part is easy...


    Fuel was dirty... couple of big chunks in it... a bit disconcerting seeing how I have two new fuel filters. I'm guessing this was in the carb for awhile.



    On the bench, before disassembly.


    Looks pretty clean, really...


    Bottom side


    Eight screws and the throttle plate comes off the main body of the carb.


    This is the retainer clip for the secondary diaphragm... don't lose this sucker, my new kit didn't come with a new one - kinda ticked me off...so keep this guy...


    Carb body with throttle plates removed. One top right, you'll see the shaft for the secondary diaphragm, and that is what the little c-clip in the previous photo retains to the throttle linkage.

    The other object in this picture is the choke, on the RHS, lower.

    At the lower left of the pic, you can see the base of the accelerator pump mechanism.




    Gasket removed, you can see for the most part, the carb looks pretty clean....



    This is the bow side fuel bowl removed, and the main metering plate is in my hand. You have to remove 6 screws to get this metering plate off. It may be stuck. If so, take a rubber mallet and gently tap. The round part in the middle is the infamous "power valve". Also notice the brass connector tube sticking out.



    This is where the main metering plate attaches to the carb body. Sorry it's a dark picture.




    Here you can see the front fuel bowl, with the accelerator pump diaphragm removed. It's 4 screws to get to this - and under it is a spring. Don't lose the spring...


    Front side of the main metering plate. The two dark brown things at the top are the main metering jets, and the other side of the power valve is seen here. Note that this picture is taken with the plate 180* out of orientation. The metering jets sit at the base of the carb.


    This is the bow side fuel bowl. I know because the accelerator pump is at the base of this one. My floats were set correctly - that is, the fuel closed off when the floats are parallel with the bowl. It's easier to understand when you're inside the carb and can play with how the floats move. They were both dirty. I disassambled, cleaned, and changed the needles and seats, readjusted the floats to the new needles and seats so they will be parallel again.


  • #2
    Close up view of how they work. It's a really simple design. Spring, needle, seat... the plastic piece just directs how the fuel fills the bowl.






    main metering plate, power valve removed.


    Here you can see the transfer tube sticking out - aluminum, allows fuel to go to the other side of the carb for the secondaries.


    Looks pretty clean, overall

    This is what you see when you remove the stern fuel bowl.
    Secondary metering plate. This sucker was *really* stock. I wound up having to use a brass drift and a hammer to get this guy loose. Be sure you're careful. You don't want to warp or nick something inadvertently.


    Once removed it looks like this...



    Get that off... and you have this guy... again...stuck...so be careful...

    Finally the main carb body...


    Removing the choke from the main body.


    Everything removed, apart, and in the carb cleaner. I soaked my parts for a day like this... then I rotated them and removed a couple other bits... On the main metering block, remove both idle screws, (on each side - and their cork gasket), and the two main jets, and make sure the transfer tube is removed as well.

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    • #3
      So... after a nice long bath... I left all the parts to soak overnight, then swished and rotated them around, and let them soak an additional day.



      HOLY CRUD!! That's a lot of gunk!


      This looks better... I rinsed all the parts in water, then a solution of dawn and water, finally finishing with clean water and then blowing them dry with compressed air.


      Floats set with new needles, seats, and the bowls cleaned. The bowls were a lot dirtier than they looked.



      This is the secondary metering valve. I didn't take pics of the assembly, but it's easy. Blue gasket, metal plate, fiber gasket, and then the aluminum plate, and the 6 clutch-head screws...



      This is the main metering side - it's the bow side of the carb... Notice the transfer tube sticking out. It has two o-rings... these supposedly can be difficult to get seated property. I just got them wet (saliva will work...) and was gentle, and it slid right in.

      Overall condition of things going back together.


      Sorry... I did a lot of assembly, and forgot to take pics...

      I did the Holly Power Valve Mod - to prevent blowing the power valve in the event of a backfire. The Holley kit has good instructions, and it's easy, and I didn't take pics...

      Anyhow...so... several things to note... Install the jets back in the metering block. NO gaskets for these. Install the cork gaskets for the idle screws. Screw these all the way down, then back them out 1.5 turns.

      If you removed the pump discharge nozzle (it's under the choke plate, held in by one phillips screw), you'll need to reinstall it. I pulled mine out, flipped the carb upside down, and there is a needle in there that will fall out. I removed this before it's bath. The kit did not come with these gaskets... so I made them. Kinda ticked me off... the Holley rebuild kit was definitely lacking some required gaskets.

      I then bolted all that together... and got ready to reinstall the secondary diaphragm...
      The secondary diaphragm is a piece of rubber sandwhiched between two rubber pieces with a spring. Get some long #8 screws - about 3 inches - two of them, and then you can screw this back together without a hassle - and without risking damaging the new gasket.

      But there was no cork gasket for where this sucker attaches to the carb body. So I made one of those too...


      I didn't take the choke apart - didn't seem to be much reason to. I did take a piece of wire and clean out the inlet passage - I couldn't easily blow air through it... with that clean it flowed air just fine. Another cork gasket was missing here, so I made another one and re-installed it.

      That pretty much button's up the entire carb... And it looks like this.



      Notice the zinc plating was removed on the carb - that's the line of color you see on the air-horn. It's not pretty right now...I'll repaint it or powder coat it this winter...but for now... it's almost ready to dunk back in the lake and go skiing.





      Clean the gasket surface on the spacer block, install new gasket, and install carb, bolting down with 4 bolts. Be sure to reconnect the choke wire, the throttle return spring, the throttle, and then the fuel inlet line. Don't forget the PCV valve either (though you may want to leave that off for tuning with a vacuum gauge).

      At this point it's worth doing several other tests. Open the throttle all the way. Using a feeling gauge set the gap on the accelerator pump (between the lever arm and the base of the carb) to .015". Then verify that your linkage adjustment is set correctly, and verify that the primary throttle blades are 100% open and vertical. The secondaries won't be - and that's ok - they're controlled by vacuum (hence that secondary vacuum diaphragm)

      With that complete... you're ready to crank her up.

      I did a dry land test... Filled up the old bucket and cranked her over. Didn't take long to fill the bowls and start. She fired right up, the choke worked perfectly, and she settled into an idle around 1000 rpm when warm. I adjusted the idle down to 800 in neutral, checked the timing, and put the cover back on. At 800 rpm with no other adjustments she's pulling 19.5" of Hg. I will wait until I'm in the water before I do final test and tune for idle (in gear, in the water, and get that to 600 rpm), and then final idle mixture.

      Check for fuel leaks. I can already tell it's smoother, more responsive, and more crisp.



      [URL=http://i215.photobucket.com/albums/cc57/sb765t/Mastercraft/carb%20rebuild/IMG_2653.jpg.html]
      [URL]
      Last edited by ncsucarjock88; 06-27-2014, 08:56 PM.

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      • #4
        Now she just needs some water. I had fun with this project. Probably should have done it a month ago...but timing just wouldn't allow. Can't wait to get her in the water this weekend and enjoy!
        Last edited by ncsucarjock88; 06-27-2014, 08:57 PM.

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        • #5
          Nice job, great pics.
          1981 stars and stripes -powerslot
          sand with red metalflake stripe

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          • #6
            Damn nice thread! Someone combine it with my 4160 rebuild thread here and make a master thread.

            I agree that the Holley kit is missing some key pieces, I lost that damn secondary retaining clip (it went flying) and had to find a new one at the hardware store.

            Comment


            • #7
              Great post and couldn't come at a better time. I've been wanting to hit the course again and have been contemplating digging my father's '87 out of storage. It hasn't been run in 11 years. I'm sure the carb is going to need rebuilt our perhaps replaced.
              2001 X-Star 5.7l LTR

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              • #8
                pretty sure if that carb has the blue gaskets in there it is not original or has been rebuilt
                the 20 year old gaskets would of been brown , just saying

                great pics and nice info

                what did u do with the floats for adjustment ,etc

                cheers


                ,,,
                sigpic

                1988 mastercraft tristar (open bow).

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                • #9
                  Can't thank you enough for this great write up...I myself have been having the same carb issues that you described in the original post....Mine is a 90' Prostar so that makes my carb almost 25 years old. Using your great pics as a reference will come in very handy when I begin my own rebuild.

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                  • #10
                    Thanks guys. I was disappointed there wasn't a better thread with pics... so I figured I'd make one.

                    Boat ran like a CHAMP today. Much smoother, more power, less throttle required, smoother holeshot, rock solid idle, and absolutely no stalling or hesitation. Choke works perfect, and she starts every time now without additional throttle required.

                    Comment


                    • #11
                      The float adjustment is easy. You just bend the tab on the float. You wan the float to be perfectly parallel with the top/bottom of the fuel bowl, with the needle valve closed.

                      In this pic... the float has a black ridge at the top of it, that needs to be parallel to the top and bottom. It's easy to see when you have the parts in your hand. If the float isn't level, gently bend the tab on the float up or down until the float is parallel, and the needle is fully closed when parallel.



                      Originally posted by pbgbottle View Post
                      pretty sure if that carb has the blue gaskets in there it is not original or has been rebuilt
                      the 20 year old gaskets would of been brown , just saying

                      great pics and nice info

                      what did u do with the floats for adjustment ,etc

                      cheers


                      ,,,

                      Comment


                      • #12
                        Nice job on the thread ncsucarjock88. Following soaking in carb cleaner, it is best to immerse the carb parts in hot water and use compressed air to dry and blow out the passages. It is important to blow these passages out as varnish and crud built up over time and softened with carb cleaner doesn't like to come out by itself. Your carb was so clean I don't suspect you will have any issues, but some of the carbs I do need a lot of work to get the passages cleaned out. Using hot water to rinse assists in the drying phase.

                        Re-assemble is best done on a clean surface. I tend to use a white towel to not introduce any contaminants to the clean carb. Dropped parts also don't tend to bounce when, not if you drop them.

                        Taking the choke housing apart is a simple process and is worthwhile to get the choke linkages clean.
                        CUSTOM WHEEL & TIRE PACKAGES
                        sigpic

                        CUSTOM DECALS - EMAIL FOR MORE INFO

                        $125 LED TRAILER LIGHT PACKAGE - FREE SHIPPING
                        REBUILDING HOLLEY MARINE CARBS - $350 DELIVERED
                        REBUILT COMPLETE MARINE HOLLEY 4160 CARBS $549 DELIVERED
                        Email - [email protected]

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                        • #13
                          I did use compressed air to blow out all the passages. Hot water isn't really available at the shop (heck, water at all requires carrying in buckets...) So water usage is kept to a minimum. Not ideal, but it is what it is. I personally prefer to use dawn and water after a water rinse to get rid of the oils from the carb degreasing. Just personal preference.... at that point they're rinsed in water (usually in the form of a yard sprayer that is used only for rinse water - great rinse with relatively low water consumption) The workbench, though it looks dirty, is actually pretty clean. Just stained from various projects... and I cleaned it before I started, knowing what I was up against. The majority of the parts were stored in a large cardboard tray, and removed only as required. I assure you... the carb project was kept plenty clean. Maybe not sterile...but I've never had an issue with any of the carbs I've rebuilt over 15 years... and I've no doubt this one will be fine as well - in fact - I know it is. The boat ran like a champ yesterday, and I put about 4 running hours on her.

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                          • #14
                            Good to hear it worked as planned. Few things better than firing up after having done some real work.

                            No offense meant as to your carb work skills. Many on here have only the rudimentary skills when it comes to working on carbs. Hats off again for your great write-up.
                            CUSTOM WHEEL & TIRE PACKAGES
                            sigpic

                            CUSTOM DECALS - EMAIL FOR MORE INFO

                            $125 LED TRAILER LIGHT PACKAGE - FREE SHIPPING
                            REBUILDING HOLLEY MARINE CARBS - $350 DELIVERED
                            REBUILT COMPLETE MARINE HOLLEY 4160 CARBS $549 DELIVERED
                            Email - [email protected]

                            Comment


                            • #15
                              I'm a trained auto tech... and the guy I share the shop with is a former aircraft tech. We're both a bit... particular. Him much moreso than myself...but yea... It's a well equipped place... air, paint booth, open blaster, closed blaster, welder, powder coater, sheetmetal punch, shear, plus the usual woodworking tools... Not too much that can't be tackled and fixed up there. This winter I will pull the engine and fix the leaking rear main seal.

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