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V4 115 carbs have fuel dripping from carb throat while running

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  • V4 115 carbs have fuel dripping from carb throat while running

    Hey everyone,

    I'm working on a project boat that was "running" terribly when I got it. It now ideals OK, but fuel litterally floods out of the bottom of each carb throat. I believe that the needle valves are not being close shut by the floats, causing fuel to pump through the bottom of each carb throat.

    I've attached a few picture of how I have the carbs set up because I'm at a complete loss for where I've gone wrong... I don't really understand how the needles are not stopping the fuel flow.

    Note: I rebuilt the carbs with new parts, including needles.

    Thanks,
    Oliver

    https://drive.google.com/open?id=1pb...9JTnmhWmfMXOzJ

    https://drive.google.com/open?id=1gW...uPlWYTmgqKaFYO

    https://drive.google.com/open?id=1ax...ZqHfJB6gw_4mBw

  • #2
    It's kinda hard to tell by the pic's posted but the float "seam" generally needs to be even with the carb body with the floats closed.
    Obviously setting the floats PROPERLY at the specified spec's are best...

    To rule out (or in) the seats leaking, you can take a vacuum gauge (I use a Mity Vac brake bleeder tool), hook it to the
    carb fuel nipple. With the floats closed, you should be able to pull a vacuum (seat and pin ARE sealing). If not, the pin/seat are leaking.


    Also, holding the carb upside down (float /needle closed), you should NOT be able to blow air (just by yourself) thru the fuel line nipple. If you can, you have sealing issues..

    Might want to also check that the floats are NOT leaking or absorbing fuel(making them open). Dunk in a small container overnight and check in the am that their not full of fuel.
    Last edited by TownsendsFJR1300; 3 weeks ago.
    Scott
    1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

    Comment


    • #3
      Hey TownsendsFJR1300,

      Thanks for the reply. I have a FSM and it directs me to set the floats at 16mm. The problem is, I'm not totally sure "where to where" I should be taking the measurement.

      Based on the fact that the I can literally flood the carbs by squeezing the primer bulb, I believe that the floats/needles are malfunctioning causing the needle to not seat and thus letting the fuel continue to flow into the carbs.

      I don't have a vacuum pump but I will try holding the carbs upside down and bowing air into the carbs.

      Oliver

      Comment


      • #4
        Well that says it - primer bulb should go hard (almost impossible to apply more pressure to go past a properly seated needle.
        Judging from the picture the properly installed float appears to be too far in (down, in respect to picture)
        I suspect the stainless steel hinge has had it,s wings bent down too far. This seems to have been done to set the float height (incorrectly).I think this was done without thinking what happens to the needle.
        As both seem the same, and both leak, this is exactly what I,d be looking at. Someone may tell you where to where 16mm is, I don’t, but the float should look level when upside down in the picture, and not sink so deeply into the top.

        Comment


        • #5
          Hi Zenoahphobic,

          Thank you for the insights. If I'm understanding your comments correctly, you're saying that the floats fall to deeply into the top of the carb when I have then turned upside down?

          This would then mean that the floats are rising too high inside the bowls when they fill with fuel?

          Thanks
          Oliver

          Comment


          • #6
            Originally posted by Oliverct View Post
            Hi Zenoahphobic,

            Thank you for the insights. If I'm understanding your comments correctly, you're saying that the floats fall to deeply into the top of the carb when I have then turned upside down?

            This would then mean that the floats are rising too high inside the bowls when they fill with fuel?

            Thanks
            Oliver
            Correct.
            I’m guessing that by looking at the last photo (problem with Forums is that we can’t be there in person to see). You haven’t placed the right float back with it’s hinge pin; that would have shown if that float has fallen too “deeply”, as you phrased it, as well.

            Comment


            • #7
              On a second look, the right float is resting on something. I wonder if they have been swapped. It seems that float would need a cutout to clear that bump, if it was meant to rise that far into the top, like the left one appears to be doing??

              Comment


              • #8
                Plus 1 ^^.

                I should clarify, the seam on the float, with the float CLOSED(up all the way), should be (IN GENERAL) about PARALLEL with the carb body float bowl EDGE..

                If the needle isn't even seating fully, it seems the floats may be incorrect..

                .You being able to "primer bulb squeeze" fuel past the needle and flood the carbs does indicate lack of sealing or as noted above, improper floats

                In the FSM, the 16 mm float level is from the SEAM of the float to either the carb body edge OR the carb body edge WITH the float gasket. Either will be very close to function properly..


                *As the engine is "new" to you and always had the issue, don't expect everything in the carb to be correct/original.. Someone's likely dinked inside it and changed parts. Suspect EVERYTHING..


                .

                .
                Last edited by TownsendsFJR1300; 3 weeks ago.
                Scott
                1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

                Comment


                • #9
                  Thank you for the clarification guys. I actually have a spare carb that I've been harvesting parts from so I will go and see if the floats in that carb match the floats in my "running" carbs.

                  I did try turning the carbs upside down and blowing air into the fuel inlet, I found that they held pressure pretty well, as long as I didn't blow to hard.

                  I'll report back shortly.

                  Oliver

                  Comment


                  • #10
                    Please post the model and year of the engine located on the transom bracket tag.

                    As already stated, who knows who picked at these carbs before.

                    Did you get new floats with the carb kits?

                    Can you post a picture with floats installed,carbs held upside down? Also post a picture of service manual page with float height adjustment?

                    Again already stated, veiwed from the side, with the carbs upside down the floats should be sitting parallel with the edge of the carb/bowl seam.When they are set this way you should not be able blow any air thru the fuel "in" line. Generally they will be very close to the factory spec then.


                    You have to adjust the little metal tab that touches the needle by bending it very carefully to get this correct. If they are the original floats I cant see them being out that much....but they look new.

                    I am just repeating everything that has already been said.

                    Please answer the questions asked and take some more pictures looking at the side view of carbs upside down.

                    Thanks

                    Comment


                    • #11
                      zfloat.jpg

                      Comment


                      • #12
                        Ah Boscoe lives. Picture is worth a thousand words.

                        Comment


                        • #13
                          Motor Specs: 1994? Yamaha V4 115 (ETLH).

                          Thank you to everyone who has helped me out!

                          I wanted to give everyone an update.

                          1) The floats were new. They were way out of spec as you all surmised. I was able to bend the tab and get them within spec.
                          2) I was able to get the motor fired up and running on it's own. Shortly after getting it to idle, I noticed that the idle was VERY high. First I looked for air leaks, found none.
                          3) After investigating I noticed that someone has messed with the idle screw, and the "glide arm" that serves as the connection point between the carb linkage assembly and the "shifter linkage".

                          I now have the motor idleing correctly.

                          Unfortunately the power trim is broken so I can't take the boat for a test run yet.

                          Oliver

                          Comment


                          • #14
                            Originally posted by zenoahphobic View Post
                            On a second look, the right float is resting on something. I wonder if they have been swapped. It seems that float would need a cutout to clear that bump, if it was meant to rise that far into the top, like the left one appears to be doing??
                            Where the hell have you been? Walkabout?

                            Comment


                            • #15
                              Originally posted by pstephens46 View Post

                              Where the hell have you been? Walkabout?
                              Yeah well, don’t really have much to contribute these days.
                              Summer holidays here, bit depressing here the whole of Australia is/has/will burn. The numerous out of control fires have joined up and look like the entire forest on the coast (inland is desert) will burn.
                              All unprecedented, state of emergency declared, military engaged and navy evacuating people by the sea as the fires are burning to the coast. Many holiday makers encircled or trapped with major road closure.
                              The smoke haze has covered Sydney, now Melbourne and Canberra (capital) with air quality there 15 times above safe level.
                              You probably get some on your news.
                              Our smoke has covered New Zealand South Island - that’s another country thousands of miles across the sea!
                              The fires now have covered areas the size of several European countries!

                              And there still are climate change denialist, inspite of authorities now admitting this is something that has never been seen before. However fatalities low (brother lost two friends, my son,s in-laws impacted badly, tomorrow Extremely bad day predicted.


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