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holley float height

10K views 4 replies 5 participants last post by  302 Z28 
#1 ·
my 750 dp has been overflowing. I made sure the fuel pressure was low so thats out. only other things would be float adjustment or something got stuck in the seat and needle. I took the carb apart and it still looks like brand new inside. not a spec of dust inside. I removed the floats and ect and checked everywhere. is there anyway i can set the float heigh while the bowls are still off? if not, where can i set them to at least get them close before i install it back on the car and get fuel all over my intake again? Thanks
 
#2 ·
Turn the bowl over where the float swings up and closes the needle and seat.
With the float in this position adjust it to where you can completely see the
two screws that hold the float on and the two top bowl attachment bolt holes.

Once its on the car and set correctly, take the bowl off again and flip the bowl
over watching the movement of the float, this way you can see where the
float is when the needle seats.
 
#3 ·
IMO ...

If this was an "all of a sudden" occurence, it's most likely dome debris that won't allow the neadle to seat. Some needles may have a viton tip, which may have degraded. Brass floats can corrode and get pinholes in them, and nitrophyl floats can become saturated ... causing (in both cases) the float to sink. There is a third type of float now, called "Duracon" which is plastic of some type. Can anyone describe them?

There are usually 2 methods that you can use to make the float level adjustment ... "dry" with the float bowls off, or "wet" with the float bowls on.
The "dry" method witll get you within the ball-park, but you should also follow that with the "wet" method.

Holley's float level adjustments (Adobe PDF file)

A 750 double-pumper (LIST # 4779-x?) almost certainly has center-pivot bowls and externally adjustable needle & seats.
 
#4 ·
invert bowl and put a 3/8 drill bit under float and adjust it there that ought to be close enough to start as a dry setting. You can also blow in the fitting and see if the needle and seat are working.



stroker444 said:
my 750 dp has been overflowing. I made sure the fuel pressure was low so thats out. only other things would be float adjustment or something got stuck in the seat and needle. I took the carb apart and it still looks like brand new inside. not a spec of dust inside. I removed the floats and ect and checked everywhere. is there anyway i can set the float heigh while the bowls are still off? if not, where can i set them to at least get them close before i install it back on the car and get fuel all over my intake again? Thanks
 
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