1977 Johnson 2 hp 2R77C Carb

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  • May 7, 2016 at 11:30 pm #4233
    PugetSoundBoater
    Participant

      I’ve rebuilt the carb and done a tune up on this motor. Having a tough time getting it to idle. Set the high speed needle 3/4 turn out ,slow speed needle 1 1/2 turns out. Running it in a barrel with the prop. After finally fine tuning the needles to get it to almost idle, I’m wondering if I have not put the needle valve packing washers in the correct order, and have a air leak because of the wrong sequence, or the packing nuts are loosening from all the adjusting. The carb kit has cork and nylon washers. I believe I put the nylon ones in the front and back of the packing. It runs like a scalded dog at high speed ,adjusted the high speed needle first,but to highest RPM or "best running" as stated in the factory repair manual. Then do the low speed needle. I should probably do this on a boat, as it kicks the water out of the barrel at high speed. I’m getting closer.
      Set the new points at .022 ,compression is around 90 after 5 pulls.
      Any things I might have missed. Thanks, jim

      "Some people want to know how a watch works, others just want to know what time it is"
      Robbie Robertson

      May 7, 2016 at 11:41 pm #36178
      wedgie
      Participant

        You can remove the prop to barrel run without soaking yourself, but you will have to do the fine tuning on a boat.

        May 7, 2016 at 11:58 pm #36180
        Mumbles
        Participant

          The packing washers should go in first, followed by the plastic one.

          If the gland nuts seem loose, just snug them up a little bit more.

          May 8, 2016 at 4:39 am #36201
          PugetSoundBoater
          Participant

            Update:I checked the new points after run a few hours during the last year. . Had them set at .022 for new points. They had worn in and were off,to about .018. Reset them to .020. Tightened the packing nuts up a bit ,didn’t check the order the packing washers were in. Reset the carb sync ,it was off a bit.
            Runs way better now ,but will need to get it on a boat for a real world carb set, and use my tach for setting the high end and idle RPM. Thanks.

            "Some people want to know how a watch works, others just want to know what time it is"
            Robbie Robertson

            May 8, 2016 at 10:53 am #36210
            jerry-ahrens
            Participant

              US Member

              I’ve seen some of those motors with a worn upper crankshaft bushing/bearing. I have a 1 1/2 Mate that has this problem. It runs good once you can get it to start, and will only idle fair at best. That will make them tough to idle down. Grab the top of the flywheel and see if you can move it fore and aft, then try it left to right. Be sure the flywheel doesn’t rotate while doing this test.

              May 8, 2016 at 12:04 pm #36215
              fleetwin
              Participant

                US Member

                Do you know any service history on this engine? When was the last time it idled OK? Does it start OK, cold and hot? You say it has plenty of WOT power, so there is hope. Usually, when these things are "worn out", they are hard to start, lousy idle, and low WOT power.
                I don’t think the order you placed the packing washers/nylon washer will affect idle needle sealing much. The fiber seal washers are placed closest to the needle tip, the nylon washer is placed closest to the packing nut.
                The carb/mag plate sync could affect lowest idle if the carb is held open at idle, or opens too soon off idle. I definitely would put this engine on a boat and try to dial it in that way.

                May 8, 2016 at 2:41 pm #36225
                PugetSoundBoater
                Participant

                  I don’t have any service history on this Craigslist motor. Didn’t idle to bad when I got it but was hard to start.
                  Since I’ve had it I did the water pump ,carb rebuild, ignition tune up minus the coil(I have a new one if needed)
                  I will try the flywheel fore aft movement today. I don’t see any oil on top of the block near this bushing/bearing .
                  It runs way better after resetting the points and carb sync. A boat test to get the carb needles set right is what’s needed.
                  Question: the omc repair manual says first adjust high speed needle to highest and best speed. I lean it out from the initial 3/4 turns ,and it really races. I don’t want to lean it out too far. Do I go for highest rpm ? Will it be too lean if I go for top RPM? Then go to set the low needle for a good idle. Manual states then go back and reset the high speed needle. Need advice here.boat trip today. Thanks, Jim

                  "Some people want to know how a watch works, others just want to know what time it is"
                  Robbie Robertson

                  May 8, 2016 at 2:59 pm #36226
                  fleetwin
                  Participant

                    US Member

                    Well, trying to adjust that high speed needle in the test tank is at best, frustrating…The engine always revs up great once the tank water has enough air in it to let the engine ventilate a bit.
                    I would go for the highest/smoothest sustainable RPM on the boat, then back it off 1/8th turn. Definitely dial in the high speed needle first, then set the low speed. You shouldn’t really need to readjust the high speed needle again unless your initial low speed adjustment was way off. But, definitely run the engine at high speed again after adjusting the low speed, make sure it accelerates OK from slow to WOT, and that it doesn’t stall out after coming back down to idle (slowly) after a WOT run.

                    May 8, 2016 at 4:04 pm #36232
                    PugetSoundBoater
                    Participant

                      Thanks for the clairification on setting the needles. Most frustrating using a barrel ,trying to keep water in there,running at high speed and adjusting all at once. Not happening very well. Will boat test and let you guys know. Thanks, Jim

                      "Some people want to know how a watch works, others just want to know what time it is"
                      Robbie Robertson

                      May 9, 2016 at 3:29 am #36271
                      PugetSoundBoater
                      Participant

                        Boat test went well, other than the wind. I traveled at least 8 miles. Got the high speed running best at 3300-3700 RPM. This is on a 12′ Lund. Got the slow speed set to abot 750 RPM. Any lower and it would die in a couple minutes. Good enough for this 90 PSi compression motor. Fleetwin,when you said "highest smoothest sustainable RPM and then back off 1/8 turn you mean turn the knob counter-clockwise,richer,correct? That’s what I did,don’t want it too lean. Runs great ,I thought I would get more RPM at top speed though. Thanks.

                        "Some people want to know how a watch works, others just want to know what time it is"
                        Robbie Robertson

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