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1988 Johnson 9.9 Carb issue.

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  • #16
    Re: 1988 Johnson 9.9 Carb issue.


    My pleasure!



    • #17
      Re: 1988 Johnson 9.9 Carb issue.

      bktheking helped so many. I often wonder what happened to him. Maybe burn out? Anyway, all you need to keep the recoil intact is a 3/8ths coarse thread nut and wind it on the center bolt. It will hold everything in place. Best of luck. Rick.


      • #18
        Re: 1988 Johnson 9.9 Carb issue.

        I have good news and not so good news.

        I rebuilt the carb. It now runs without the choke out. I do not have to spray 50:1 into the carb to start it either. Situation has improved.

        Unfortunately it still wont run longer than 1 minute. I have went over everything. Replaced and tested the fuel pump. Working. Fuel lines new. Tank line new. Bulb new. The tank is an old metal tank. It is supposedly self venting through the cap but I took the cap off just to be sure.

        The bulb pumps up nice and solid. No leaks, unless I squeeze really really hard and then some fuel will leak out around the metal clamp on the output side of the bulb, but like I said I have to squeeze real hard. Does anyone else's do that if you squeeze real hard?

        I am just grasping at straws here, but I cannot figure this out. I mean, if there was an air leak between tank and carb, wouldn't the fuel pump test fail? (by test I mean when I unhook fuel line from carb and pull rope, gas squirts real good out hose.)

        I feel like the float is working properly because I did a blow test when I was assembling it and the needle functioned well. New needle, new seat, needle clip on proper.

        I guess the next step is to eliminate the tank, hoses and pump from the picture.

        I read somewhere about building an IV drip style fuel source. Essentially a 2 liter bottle with bottom removed, inverted with some sort of hose attachment in bottle cap hung above motor with line running directly into carb.

        Like I said, I have made progress, but still not running longer than 1 minute.

        Any thoughts?


        • #19
          Re: 1988 Johnson 9.9 Carb issue.

          Before you try that, try elevating your tank well above the engine. A couple of feet higher. At that point you have a gravity feed fuel system once the motor is started and it should eliminate any pump concerns. IMO it is probably either your pump or the carb. float is sticking closed. Your fuel line should not leak no matter how hard you pump it so I would fix that ASAP. I know you have an aggravating problem but stick with it and you will solve it eventually. Rick.


          • #20
            Re: 1988 Johnson 9.9 Carb issue.

            Unfortunately I already had the tank elevated.

            I rebuilt the carb and replaced the float, needle, o ring and seat with new stuff. I tested the needle by blowing into the input with the carb right side up and with it upside down and it stopped the air flow, and when I turned it back over it flowed again. I did this both before and after assembly. As fragile as plastic top is I dread having to take it all apart again.

            I am almost willing to buy a carb that has been rebuilt and tested so that I can mount it and see if that fixes it. If it does, it would be worth it if the price wasn't too high. I see them for around $150 but that is not tuned and tested. Anyone ever hear of such a thing as a carb that is ready to run?


            • #21
              Re: 1988 Johnson 9.9 Carb issue.

              Todays game plan:

              Going to the local hardware store and buying clear tube to temporarily replace the line from pump to carb. Going to monitor the tube for fuel flow and possible bubbles. If I see bubbles then obviously I have an air leak into the line (which at this point I am praying for).

              If that test passes (no bubbles) I will be unfortunately removing the carb and opening it up again. I would like to see if the little rubber idle tube inside the bowl is interfering with the float action. I made sure the dogleg was pointing in towards the nozzle well, but you nenver know once that thing gets sealed up maybe it moves under fuel pressure and obrstructs the float from falling back down and preventing it from leveraging the needle open.

              But will go after the clear line first. I want to avoid popping that that carb off again if I can, I fear damaging that plastic top.

              And again, thanks to yall for sticking with me. The confidence I have from this forum is so valuable. I would never have gotten this far with the iboats communitiy.


              • #22
                Re: 1988 Johnson 9.9 Carb issue.

                Louisville, I have not tried this myself yet but you may wish to bite the bullet and get that top cover. I do not know if that will work but just got back from my buddy at Dick's near Chain O'Lakes IL. He is bout to retire but there is nothing he doesnt have for any older motors. That aside you will shortly see under a new post a photo of the back of my carb and if that is not warpage, I do not know what is - if I am smart enough to post the pic. Motor is my uncles and he has to pull and pull to get started and has rough time idling. It may be your issue. Kit withy needle is $100 though. Just a thought and I will advise results when done. Good luck to you and your team tomorrow if you are watchin the finals.


                • #23
                  Re: 1988 Johnson 9.9 Carb issue.

                  Louisville, a little clarification please. You said it will not run longer then a minute. Does it run longer if you continue to pump the primer bulb every 30 seconds or so. If not, then fuel pumping is most likely not your problem.

                  I will assume you tried to pump the bulb and it still died, so we are back to your carb providing too lean of mixture since you said it still requires a choke. First check. How did you set your slow speed needle after cleaning the carb? Have you tried turning that needle another 1/2 turn to a full turn counter-clockwise and did it help? If no, then I suspect your slow speed circuit in your carb is still causing you a problem.


                  • #24
                    Re: 1988 Johnson 9.9 Carb issue.


                    Yes, it definitely helped to pump the bulb, not always, but usually. Yes, I have been all over the dial with respect to the slow speed needle. Also, I actually corrected the choke issue in post #18, it was a clogged brass tube in the nozzle well where the little rubber pipe connects to the nozzle assembly.

                    To All,

                    I actually have some major updates for this post. I have made serious progress.

                    #1: I added the clear line so so I could watch flow. Turns out there was NO FLOW! In my original post I stated that I tested the old pump by disconnecting the line from carb and pulled rope. A fair amount of fuel squirted out demonstrating that the pump is pushing fine. but I already purchased a pump (I jumped the gun and bought one...will prove to be foolish move later in post) so I just went ahead and installed it..insurance against future failure I guess.

                    Well, after seeing that there was no flow coming through the clear tube I was like "that pump is brand new it cant be bad!". So again, I tested it by disconnecting the newly replaced clear line from the carb and guess what. No squirt!!

                    So I put the old one back on, do the same test right off the bat and squirt! I reconnected lines, primed bulb and fired it up. It was a bit hard to start (as it it has been) but this time it stayed running for 30 minutes! I eventually turned off the motor myself (pulled deadman plug which I am assuming is the proper way to shut down other than running dry). I restarted it several times there after, first pull each time.

                    What are the odds the old pump works and the new pump doesn't? Pretty slim but I am sticking with the old for now.

                    Now I am not declaring victory yet, but there are some lessons for me in here. One of them is I jumped the gun and bought a pump BEFORE I tested the old based on reading and such. I should only spend money based on TESTING, not reading. Had I taken the proper steps first I would have saved money ($45 for new pump) and I would not have went down all these other paths diagnosing problems that did not exist had I demonstrated conservative logic and patience.

                    More testing and tuning to follow but like I said. Major progress.

                    Now for a second update:

                    #2. I broke my plastic carb top. It broke where the cam roller screws into the top. I was trying to turn the carb/manifold nut and my wrench slipped and whack! Knocked the bolt right out the plastic thread hole and took a good chunk of the top with it.

                    I managed to JB Weld the chunk back on to the top but the bolt threads are shot so the roller has horrible play in it.

                    Click image for larger version

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                    Amazingly the top still functions, at least enough to get me to this point. But I MUST buy a new top ASAP, as in now! This fix will fail at the worst time and will probably create warpage to boot.

                    I understand there are several (at least two) types of tops. Does anyone have any insight as to what I should be looking for. I need to replace the cam roller as well so I would like to buy them both at the same time. Should I be looking for the same type of top with the metal bolt, or will the new style with the roller cam bolt built into the plastic?


                    • #25
                      Re: 1988 Johnson 9.9 Carb issue.

                      Take the fuel pump off the crancase with the fuel lines still attached. Pump the bulb. Does fuel come out the back side of the fuel pump.? If so bad main diaphram in the pump.


                      • #26
                        Re: 1988 Johnson 9.9 Carb issue.

                        I already took the new one off. I will test it next again once I get everything running consistent. I really want to replace that top.

                        I found one at ***************** and I am wondering if this one is compatible with my carb. I have a 1988 9.9 plastic top carb with the screw in cam roller stud. This one has the molded stud. Can anyone verify that these are interchangeable?

                        Link to new top ($100) and new roller cam is $15. Anyone know?

                        Evinrude Johnson OMC 0433973 - Carburetor Cover Kit @ *****************


                        • #27
                          Re: 1988 Johnson 9.9 Carb issue.

                          I ended up purchasing the new top. I spoke with a person on the phone who assured me they are compatible. I also ordered a new cam, roller and bracket to replace my broken sleeve.



                          • #28
                            Re: 1988 Johnson 9.9 Carb issue.

                            Oh, one other thing. You said you replaced the fuel lines on the motor but what about on the tank? After a recent thread on fuel hoses I changed all mine and added an inline fuel filter at the end of the tank hose right before it attaches to the motor (very cheap insurance). You could have a nice clean fuel system on the motor but re-shmutzing it with crap from your tank or tank lines. There is a screen inside the fuel pump that could get clogged. You may have clogged the new pump. I wouldn't buy a new carb, you can fix this and learn a lot in the process.


                            • #29
                              Re: 1988 Johnson 9.9 Carb issue.

                              Louisville - sorry about that. I was beat after Sunday night. The top cover kit is $99 - hope you got a better deal i could not find it online any cheaper. Gasket was also in there did most of the rebuild last night. Now to zip it all up.............I'll post on measuring 8 inch pounds on my own thread. Congrats to the Cards.


                              • #30
                                Sign up today
                                Re: 1988 Johnson 9.9 Carb issue.

                                Still alive and well! I didn't burn out, switched hobbies is all. I still have my boat and a couple of motors lol.
                                sigpicSignature- If you have fuel and spark- Have you checked compression?