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1986 pro v 150 carbs replacement

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  • 1986 pro v 150 carbs replacement

    Been a while I have been here. I want to know if there is any newer carbs that I can install on my pro v 150? Long story is I am tired of rebuilding theses carbs. Been thru them over a dozen time with multiple new kits. Cleaned them completely each time. I mean fully gone through. The problem is they keep flooding out. Was out yesterday and started it up. Sounded like it would run a few seconds then die. Did this 5 times. I removed the cowl and there was a ton up fuel all over the carbs. I mean at least a pint in the bottom of cowl. Replaced all fuel lines and drained both fuel tanks then cleaned them very clean. So been the the entire fuel system. Pumps are less than 2 years old. After each time going thru carbs I have linked and sync. My fist thought was the needles fell off or got stuck open but on all 3? So now I am wanting to replace them with some newer carbs that would fit my engine. Ran out of other things to think of.
    Thank you

  • #2
    Sounds like float needles are not sealing properly and overflowing the bowls. From your post you have replaced the needle valves several times., but what are the valve seats like? If they are worn then it will be difficult to get a good seal even with new needle's. They can be lapped...it may work or not.

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    • #3
      I did lap the valve seats. The seats canot be replaced and I use oem needles. Float every time are set to specs.

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      • #4
        have you looked to see which carbs are leaking fuel?

        do they leak when pumping the primer bulb, or just when running?

        Have you replaced the floats?

        did you use a sonic cleaner?


        trash in the lines or pumps can hide and hit after cranking back up causing the needles from shutting off the fuel flow.

        ​​​​​​​have you measured fuel pressure to see how high it is when running or trying to run?
        Last edited by 99yam40; 1 week ago.

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        • #5
          The last time all three were leaking. Only pumped ball when first started. I have not replaced floats but did do under water test with no leaks. I have cleaned or replaced all fuel lines and fresh fuel. When it did start it fludded out. Almost a pint. Just found a deal on another set of carbs and will try them out. Just can't figure why all three carbs would flood with so much dumped fuel.

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          • #6
            With each carb off and if you have a vacuum tester (with gauge such as a Mityvac), hook up the gauge to the fuel inlet nipple.

            With the carb upside down, the float will close the needle and seat. Now, try pulling a vacuum, you shouldn't get ANY leakage.
            Any leakage indicates the needle and/or seat leaking...

            I do this with all carbs I go thru...

            I'd also check the floats by removing from the carb, and hold under water overnight. once out of the water, shake/check for any water intrusion..


            .
            Scott
            1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

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            • #7
              I did the same water test as you said. They passed
              I have a mighty vac and will try that test.

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              • #8
                I have a 1988 150 with Nikki carbs (two floats/bowls per carb) and one of the carbs started flooding after I had cleaned and rebuilt them. What I found was that the float was sticking on the carb housing and it would not seal when full. I was going to order new (OEM) bowls but first tried swapping the floats in the leaking carb with another one and this solved the problem. The tolerance/gap between the housing and the float is very small and I think the plastic floats may get a little bit larger over the years and then start sticking.

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                • #9
                  Thanks Todd
                  that makes lot of since. Not sure how to check it but great idea. I do have another full set of oem carbs coming. They are used and I will rebuild them before installing. It sounds like luck you found that out on yours. Guess only other way is to buy new floats.

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                  • #10
                    Those floats are adjustable, correct? Are you sure you have the float level set correctly as per SM. Have them set just a little bit off and the carbs will overflow...

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                    • #11
                      Yes they were set according to the manual. Each time I pulled them apart they were still on the money.

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                      • #12
                        Could the needle(s) be jamming in the bore? Corrosion or varnish could make them stick - a good polish with a bud might help. Use something like a cutting wax, but be careful to clean out thoroughly.
                        All work should be very carefully done. Nothing should actually be bent to meet tolerances; misalignment can occur.
                        Short of all the above including what other posters have said, the only other way all three seats could leak is by a common cause, that is fuel. Could you have fine rubbish coming thru in the fuel - such as disintegrating fuel lines by the use of ethanol gasoline?

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                        • #13
                          I used valve cutting stuff very gently. I used a needle to shape some then cleaned out the seat and polished with a q tip. The seats on these carbs cannot be replaced. So looking at 34 year old seats. I did use oem needles. I don't know the history of my carbs before me but the condition they were when I got them was really gunked up. I did a good soak and every port or holes was also done. I know these carbs really good after about a dozen tear downs. One carb bowl has the drain screw missing and hole epoxied. Your thought about maybe something was bent could be a factor. This last time I tore them down i didn't put fuel in them and then started my motor and ran fine while on the muffs. The next day went to the lake and right off the bat they flooded bad. All the filter and hose have been replaced. Drained both fuel tanks and took the sender out for access to inside tank clean the inside. Blew out
                          the lines. Fresh fuel was put in to the cleaned

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                          • #14
                            Just to add to your above post, if I have any doubt about a carb leaking/not sealing, I use a small, mower gas tank (plastic with a shut off valve).

                            I'll hook that up to the carb intake nipple, (use gravity), turn on the fuel valve and check for any excess fuel running out while still on the bench.

                            Of course you can tilt the carbs some to check and see if it leaks.

                            For sticky carb needle and "guide", I'll use toothpaste or a light metal cleaner (like Maquires) and a Q-Tip in a drill motor and run it up and down in the bore.. Works really well..


                            *We did my neighbors 200 carbs many years back and one carb leaked out the throat. Further examination showed the float hanging up on the bowl to carb body gasket...
                            I suspect you have rubber seals in the float bowls themselves..

                            .


                            .


                            .
                            Scott
                            1997 Angler 204, Center Console powered by a 2006 Yamaha F150TXR

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                            • #15
                              I'm seaing a lot of floats swelling and sticking to the inside of the bowl. Also float drop is often overlooked. If you invert (upside down) and blow thru the carb intake. It should not pass any air.then turn upside right and blow
                              It should let air pass thru
                              Also a good trick is to shake the carb before reinstalling and hear the float and needle move up and down.
                              (WEBER carb ref for many years)

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