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NS90a help- fuel pours out throat of lower carb

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poedy66

New member
Driving me batty! Have just redone gearcase, pump and cleaned carbs on recent purchase. Motor seems to run fine at idle and forward high speed while using ear muffs. Problem is shortly after it starts, fuel pours (not drips) out the lower carb while running. I have checked float & needle with magnifying glass, immersed float to check it, and finally switched float and needle with those from top carb - same result. Vent passage to bowl is clear. Possibly needle seat, but as best as I can see it is okay. My first experience with Nissans, but never seen a carb do this. Any ideas will be most appreciated. 1990-92 model year
 
Thanks for reply - float is molded hard plastic and has no adjustable tang. height is same as other two carbs which do not leak
 
yep the needle or needle seat is bad letting fuel continuously flow flooding the carb until it pours out the front, this is a fire hazard.

take it out and remove the seat and be sure its not just blocked open by trash, if it looks fine then replace the needle and seat for that carb to fix it
 
keakar said:
yep the needle or needle seat is bad letting fuel continuously flow flooding the carb until it pours out the front, this is a fire hazard.

take it out and remove the seat and be sure its not just blocked open by trash, if it looks fine then replace the needle and seat for that carb to fix it
Click to expand...

Really? How would you remove the seat? What would you use to replace it?
If the seat is bad, though I have never seen that condition, you must replace the carb body.
The rubber (nitrile, maybe) tip on the sat can wear, though.
 
pvanv said:
Really? How would you remove the seat? What would you use to replace it?
If the seat is bad, though I have never seen that condition, you must replace the carb body.
The rubber (nitrile, maybe) tip on the sat can wear, though.
Click to expand...

not every carb has removable and replaceable float needle seats nor does every carb have seats that are cast an not removable

my diagnosis was correct and in agreement with yours regardless of the seat being removable or not and this would be obvious as soon as he opened the carb to check it
 
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