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

Car idles fine but floatbowl gets filled after high revs

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Old Jul 16, 2007 | 09:05 PM
  #1  
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Car idles fine but floatbowl gets filled after high revs

Hi,

So I tried to fix the problem, this is what happened.

https://www.rx7club.com/1st-generation-specific-1979-1985-18/my-car-wont-idle-correctly-dies-if-i-let-go-off-gas-pedal-664972/

I tried to adjust the floats today... the needle and seat... cleaning it with carb cleaner and stuff... car would stay idle fine, but once I drive it around... rev it a bit hard... then the float bowl will start to fill up. This is only for one of the floats... not both. I am not sure why? I took it out, everything looks fine and stuff... it's just weird and I can't understand... what else can it be?? It's the floats near the firewall side... please let me know if you have any idea... I try to get this fixed.

Could it be the needle and seat being worn out or something?

Mack
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Old Jul 17, 2007 | 11:02 PM
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Originally Posted by tigermack

Could it be the needle and seat being worn out or something?

Mack
Sure sounds like it. Are you running a std fuel pump?
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Old Jul 18, 2007 | 01:34 AM
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I have been working on the car with him. The car has a carter fuel pump and a holley fpr set to 2.5psi
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Old Jul 18, 2007 | 10:57 AM
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Why did you go messing with your floats?

For the heck of it, you might as well get a rebuild kit and replace the needles and seats. It can't hurt, and they do wear out over time.

Once you mess with a set of floats, it's damn near impossible to get them right again.... I'm the kind of guy who'd skip the headache and just get a new set of floats, since they're adjusted properly from the factory.

Jon
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Old Jul 18, 2007 | 11:24 AM
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Originally Posted by vipernicus42
Why did you go messing with your floats?

For the heck of it, you might as well get a rebuild kit and replace the needles and seats. It can't hurt, and they do wear out over time.

Once you mess with a set of floats, it's damn near impossible to get them right again.... I'm the kind of guy who'd skip the headache and just get a new set of floats, since they're adjusted properly from the factory.

Jon
It is a Yaw carb and the rear float level had been overfilling.
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Old Jul 18, 2007 | 12:55 PM
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Yaw uses the same floats, needles and seats as everyone else, so I'd just go ahead and replace them.

Jon
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Old Jul 18, 2007 | 04:54 PM
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Yaw carb or not, one does not mess with the float adjustment unless all other avenues have been eliminated. More people fuckup a good carb adjustment by changing the float levels than they do resetting them correctly.
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Old Jul 18, 2007 | 05:15 PM
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He had posted on the other thread, he changed the fuel filter, checked vaccum leak and did everything that was suggested. Won't the float overfilling appear in both the front and rear floats if it is a problem in another area?
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Old Jul 18, 2007 | 05:21 PM
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If you have a caliper - setting the floats should be an easy process. On my Yaw, it took .80 of clearance b/w the top carb plate and the bottom of the float (per FSM says .63). My floats were F'up. Like .20 something one side and .34 other. Damn thing would overflow like a running toilet.

But it sounds to me like your needle may be sticking. I agree w/ the crew on here - get the rebuild kit.
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Old Jul 18, 2007 | 05:27 PM
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Thanks for all of you guys' help. I will get a rebuild kit asap.
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Old Jul 20, 2007 | 07:03 PM
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Thank you all, just got a rebuild kit with the float needles. I will let you guys updated if this will solve the problem or not. Thank you!!
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Old Jul 20, 2007 | 09:00 PM
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I need to pick up a rebuild kit. Where can I get one for the 4bl Nikki?
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Old Jul 30, 2007 | 11:39 AM
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UPDATE:

So I got the rebuild kit from Mazdatrix, switched the needle/seat, etc that's always filling up... it worked. Only problem is... when I first messed with the tap on the float... I just had to readjust it, so now the floatbowl stays a little bit lower than usual or the other one... it's not at the half way mark. Does it matter? Also, on 3rd gear when I go full throttle at higher RPM... the car bogs... it won't give power and choke a bit... is it because I am running too lean? Does the level of the float bowl has anything to do with that? Any help would be appreciated. Thanks.
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Old Jul 30, 2007 | 01:13 PM
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You could be starving at high rpms now, due to the low fuel level in the float bowls. You have already changed the filter, right?
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Old Jul 30, 2007 | 03:05 PM
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check the acceleration pump system for fuel delivery . remember its a Yaw carb so it flows more air than stock. As such at the instantanious demand for more air flow the fuel system is not keeping pace. Perhaps the person who had this carb before you tried overompensating by overfilling the one float bowl.
read Paul Yaws articles for details. http://www.yawpower.com/niktest.html
http://www.yawpower.com/techindx.html
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Old Jul 30, 2007 | 04:42 PM
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Originally Posted by Kentetsu
You could be starving at high rpms now, due to the low fuel level in the float bowls. You have already changed the filter, right?
Yes, filters been changed. Both of them.
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Old Aug 6, 2007 | 09:13 PM
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I don't know what's going on again... I tried to adjust the problem and it happens again... it's filling up after its warmed up and high revs.
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