1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

how to adjust float levels?

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Old 08-24-11 | 12:02 PM
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how to adjust float levels?

Okay, after pretty much replacing everything and trying all I can to prevent this car from running too rich I have come to the conclusion my float levels have got to be the problem. They were a little high to begin with but they were not too bad and I figured it would not really cause a problem. (Obviously I was in denial.) I have been told it is a pain in the *** to adjust these float levels but I have no choice but to give it a shot. So I am wondering how to go about adjusting the levels and the easiest way to get it as accurate as possible.
Old 08-24-11 | 12:30 PM
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From: Loxahatchee, FL
Originally Posted by bahlorm
Okay, after pretty much replacing everything and trying all I can to prevent this car from running too rich I have come to the conclusion my float levels have got to be the problem. They were a little high to begin with but they were not too bad and I figured it would not really cause a problem. (Obviously I was in denial.) I have been told it is a pain in the *** to adjust these float levels but I have no choice but to give it a shot. So I am wondering how to go about adjusting the levels and the easiest way to get it as accurate as possible.
Use a caliper to measure the float level in the "up" and "down" position. You'll have to carefully bend the tabs to adjust for height, just be patient and make small adjustments until your back in factory spec. If you need the specs just let me know and I'll look them up for you.
Old 08-24-11 | 12:48 PM
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From: Loxahatchee, FL
Here is the float level adjustment page out of the manual with the specs for a later model Nikki
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Float Level Adjustment.pdf (98.7 KB, 1263 views)
Old 08-24-11 | 01:05 PM
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Okay, so let me make sure I understand this correctly. To measure it I first have the air horn upside down to where the floats would be leaking towards the air horn. I then measure the seat lip (not too sure exactly what the seat lip is) and it should come out between .62 and .02 inch? Then I flip it over to let the float levels dangle and measure the bottom of the flat to the air horn gasket and it should measure between 2 and .02 of an inch? That doesn't sound correct but what I am getting from that lol. I obviously am not the brightest crayon in the box.
Old 08-24-11 | 01:29 PM
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From: Loxahatchee, FL
Originally Posted by bahlorm
Okay, so let me make sure I understand this correctly. To measure it I first have the air horn upside down to where the floats would be leaking towards the air horn. I then measure the seat lip (not too sure exactly what the seat lip is) and it should come out between .62 and .02 inch? Then I flip it over to let the float levels dangle and measure the bottom of the flat to the air horn gasket and it should measure between 2 and .02 of an inch? That doesn't sound correct but what I am getting from that lol. I obviously am not the brightest crayon in the box.
Close, the way to read that is .62 plus (+) or minus (-) .02 inch (tolerance)... meaning between .60 and .64 inch... and for the other measurement it's 2 plus or minus .02 inch (tolerance)... meaning between 1.98 and 2.02 inches.

I would use the mm measurements, much easier to measure and read on a caliper or ruler. And make sure you look at the diagram to see where you measure from on the float. The "H" is from the top of the float (upside down) and the "L" measurement is from the bottom of the float (right side up).

Let me know if you have any other questions.
Old 08-24-11 | 01:43 PM
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You don't. That's the short answer.

Unless the carb has been dropped, or you have a very good reason to believe that they are set wrong, you are far better off just leaving them alone. 99 times out of 100 it seems to only cause issues that later have to be gone over again.

Good luck....




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Old 08-24-11 | 01:50 PM
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From: Loxahatchee, FL
Originally Posted by Kentetsu
You don't. That's the short answer.

Unless the carb has been dropped, or you have a very good reason to believe that they are set wrong, you are far better off just leaving them alone. 99 times out of 100 it seems to only cause issues that later have to be gone over again.

Good luck....




.
No harm in checking the tolerances though. If you measure the floats and find they're within factory parameters; you've then ruled that out as the problem. It takes 5 minutes to do so you might as well do it to rule out a variable.
Old 08-24-11 | 02:33 PM
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Well I have put in new floats and after all the times I have taken the air horn off the car there is a possibility they may of gone a little out of wack. The level is a little higher than it should but I never thought it would make a big difference, but with me working on this car and my friend who is pretty knowledgeable about carburetors and mechanics in general has ruled out most everything but something wrong internally with the carb. Which I have already rebuilt the carb with no luck. But I would assume with the float levels a little high it would cause the car to run a little too rich. And it runs rich enough to where it hesitates and at high rpm it starts smoking (or when I start it when its cold.) But idling and acceleration it really has no noticeable problem.
Old 08-24-11 | 03:36 PM
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Correct me if I am wrong, but if your float level was set too high, you would more than likely behave opposite from how you describe. It would flood at idle and the car would be fine at speed (cant run too rich with the hammer down on these things). I too am struggling with my nikki, but most of it is my own fault...lol.
Old 08-24-11 | 05:02 PM
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Ah I would have no idea on that one cfamily. I have replaced the plugs, wires, dist cap and rotor, got a new fuel pump, holly fuel regulator thats set at 2 psi, rebuilt the carb, and had it timed correctly. I also spent hours checking for vacuum leaks with no success. As well as replacing the 3 fuel filters that was located on this car. And it still boggs down when idling, smokes when I start it and its cold outside, hard to start, and smokes when I get on it at about 6k+. And the colder it gets in the morning the worse it seems to be. It used to take me maybe 30 second to start it, now it has gotten to where it is taking a couple minutes and a few tries after its turned over. It just wont start without putting on the gas and when I push on it too much it bogs down and kills itself.
Old 08-24-11 | 06:26 PM
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Looking at the carb floats the one in the back was low and the one up front was high, I tried to measure them with the directions above and they did not read right. With them laying flat 1 of them was all the way to 1 inch instead of .62! Then the other way the other was off by a little bit but not as much. Now I will just set it on and see what happens.
Old 08-24-11 | 08:03 PM
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Trickiest bit is figuring out WHERE on the float to measure. All the manuals I've seen are a bit less that precise on the subject, generally pointing to a corner of the float that is radiused, not sharp.

Sight glass during operation is the only way to truly know. Which makes tweaking them tedious, to say the least.
Old 08-24-11 | 11:19 PM
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Originally Posted by DivinDriver
Sight glass during operation is the only way to truly know. Which makes tweaking them tedious, to say the least.
Spot on. Don't worry about the measurements so much as the fuel levels in the sight glass. Also float drop is not really that important, so long as its not so low that the needles can fall down so far that they get stuck open. The important measurement is float level (where you turn the air horn upside down). As long as they are even and your fuel level is roughly centred in the sight glass that is all you need to worry about.
Old 08-25-11 | 04:36 AM
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Don't forget that fuel pressure can mess with your levels in your float bowl too, if the pressure is too high.
Old 08-25-11 | 07:57 AM
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Yeah that is true Kent. My gauge on there has been anywhere from 0 to 3 psi while the cars running. When it has registered a certain psi I have justed it down to 2, but after spending $30 on this gauge it seems to not read very accurately after being told it would for such low psi.
Old 08-25-11 | 10:03 AM
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Maybe it's not your gauge, but your pump that's operating erratically?

Stock pump pressure for a Nikki is 3.7 to 4.7 PSI...
Old 08-25-11 | 11:08 AM
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I hope it is not my pump. I just replaced it last weekend after my last pump went out on me. Found another filter on the car that was clogged (making 3 fuel filters) and when I fixed it the fuel pump just gave up on me. I replaced it with a Mr gasket 7 psi fuel pump because it was the only thing I could get to keep the car running.
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