’78 70hp choke override reset spring position

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  • March 6, 2017 at 3:17 am #6479
    johnyrude200
    Participant

      I can’t seem to find any pictures or descriptions in the old service manual, or pictures in parts diagrams, showing how to put this spring back to where it is supposed to be.

      The purpose of the spring is to open the choke flaps back up after you engage the choke solenoid via the key switch. I can’t seem to figure out how to monkey this spring back to the right position!

      Does anyone have a picture of how one of these springs is supposed to sit on the middle carb to open the choke flaps back up?

      March 6, 2017 at 3:24 am #53925
      Mumbles
      Participant

        I can visualize it and have done it but I can’t explain it!

        Not sure if I have any photos but I do have some manifolds and carbs squirreled away which might still have the spring intact. Sometime tomorrow will be the earliest I can find them.

        March 6, 2017 at 3:42 am #53927
        johnyrude200
        Participant

          Thank you so much, explaining I think would be impossible, but a picture….WORTH A MILLION BUCKS!

          March 6, 2017 at 3:43 am #53928
          Mumbles
          Participant

            Here’s a grainy photo from the interweb. It’s a starting point.

            My bank account number is XXX XXX XXX XXX.

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            March 6, 2017 at 3:55 am #53929
            johnyrude200
            Participant

              The spring I’m talking about is the one in the picture you can’t really see – to the left is the brass throttle arm cam follower, and near the bottom you see a little silver line which is the hook end of the spring. The other end extends out and >SHOULD< push the choke flap lever back to the open position when you let off the choke solenoid key position.

              I don’t see in the picture how that spring reaches to the right and pushes that 2nd brass fixture down. Or am I missing this completely?

              I’ll take a picture tomorrow and post if we can’t get this sorted.

              March 6, 2017 at 7:40 am #53930
              frankr
              Participant

                US Member

                I dunno, I do think either you or I you are missing it completely. I’m thinking the spring you are looking at is to close the throttle butterfly shaft. But my rememberer may be kaput.

                This is what I have, for whatever it is worth.

                image url upload

                March 6, 2017 at 2:31 pm #53935
                fleetwin
                Participant

                  US Member - 2 Years

                  OK, I "think" I know what you are referring to. Although, in Mumbles’ picture the spring/arm appears to have been wrapped back on the carb throttle arm and tucked under the roller….What is referred to as the over ride spring in Frank’s diagram seems to be in the wrong position or named poorly.
                  There should be a spring/arm wrapped around the center carb shaft arm that extends out to the choke shaft and lever. The purpose of this spring is to "over ride" the two stage choke warm up solenoid in the event that the engine was started cold and immediately accelerated hard to WOT in gear. When the throttle is opened wide, the spring/arm in question comes down onto the choke shaft and lever brass arm pushing the choke open, "over riding" the choke "warm up" solenoid. The engine would flood rich/stall due to the partially closed choke if this situation occurred and the spring/arm was not in place/working properly.
                  In reality, most of these two stage choke solenoids were rewired to defeat this feature. In other words, both choke solenoid purple leads were wired to the choke switch on the control box leaving the thermal warm up switch doing nothing at all.
                  Sorry, I know I could blabber on for days about this, but what you need is a picture. Like I say, the spring I think you are referring to has been bent back out of the way in Mumbles’ picture. Perhaps you can post a picture so I will know if this spring is what you are referring to….D

                  PS Rereading your post, you mention this engine is a 1978 70hp, the system I am referring to was not used in 1978. So, I guess I have wasted your time unless your engine is older than 1978.
                  The pesky little bugger I am referring to is item 54 on the enclosed diagram:
                  http://www.marineengine.com/parts/johns … e+Manifold

                  And after researching some more, I see that this spring was indeed used on the 1978 models, even though the two stage choke solenoid was not.

                  March 6, 2017 at 3:55 pm #53942
                  johnyrude200
                  Participant

                    Here are pics to explain things better. I pulled the carbs to clean/inspect for a service order and putting it back together, I can’t remember how this spring goes back on! Hence my plea for assistance!

                    The last picture shows how the choke flaps are staying partially shut when I let off the key switch/choke solenoid. I suppose they would probably just open up once the motor is running but it needs to be done right.

                    I believe the center hole on the spring goes around the little plastic keeper on the left brass hardware, and the hook loops under it to set it in place. The ‘arm’ of the spring reaches over the choke flap brass piece and tensions it back down to swing the flaps open when you let off the key. But when I put this on in this configuration, it doesn’t do it’s job. It was working when I pulled it apart, so I’m missing something here.



                    March 6, 2017 at 6:56 pm #53949
                    Mumbles
                    Participant

                      I’m pretty sure the choke butterflies open by gravity and airflow past them. The spring makes sure they open as the throttle is advanced.

                      In the photos you can see how the butterfly shafts are offset with the larger half of the butterfly on top of the shaft making them top heavy. Also, the weight and geometry of the linkage will help to open them. The spring slides onto the nylon bushing before it is snapped into the throttle linkage plate and the long end goes over top of the choke linkage.

                      Take your time to synch these carbs as the 70’s seem sensitive to it and they don’t make a lot of torque anyway coming off idle to get a boat on plane. Three alligator clips with a short length of wire in each one and clipped onto the throttle shafts on the port side will make the job easier. Any movement of the shafts will be amplified by the clips and you will be able to see all three tips of the wires moving as the center carb is opened. Have fun! 😀

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                      March 6, 2017 at 7:11 pm #53952
                      johnyrude200
                      Participant

                        Thanks Mumbles, glad I wasn’t going crazy. I had the spring in the right spot, but thought it was supposed to apply a downward force on that brass carb hardware. I see in your picture it is set up the same way the one I have here is.

                        One thing I noticed is this old 70 does not have a low speed adjustment, just fixed high and low speed jets. I can see why they might be so sensitive to the rear carb throttle flap opening/closing too soon.

                        I use that amplifier on an alligator all the time, can’t fix most of these motors the right way without one (or three!!!!) 😯

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