Why is my Holley Ultra HP 950 flooding?

[SKeown]

My thinking about the dial caliper is, just say that the gas port is right next to the o-ring and the o-ring cant seal. A quick measurement will tell you if the gas port is ''centered'' between the o-rings.

There's only one O-ring on the N&S, I can feel them enguaging when screwing into the bowl.
With the identical fuel supply system to the carb I never experienced this with my previous Holley 950 HP, just since changing to the Ultra HP.

SKeown

[BrazilianZ28Camaro]

Even with jet extensions you boosters will loose prime if the PV is uncovered, particularly with the Ultra series carbs, their PV is located higher and the bowls are larger. I picked up .4 by removing the PV and going from 90 to 99 jets in the rear.

SKeown

Skeown , have you seen this in sideways T-ram aplications?

I'm under impression these carbs are tuned to T-ram aplications and be bolted sideways, but not advertised by Holley.

The secondary PV & adjustable opening secondaries suggest me that.

[flashgordon]

Sorry guys to rehash an old thread but my holley 950 ultra hp is doing the exact same thing and I can't get answers as to why, even from holley, does anyone have the answer to why these carbs are flooding out from the primary bowl yet the fuel level in the bowl is sitting at about half the sight glass? Thanks

[BrazilianZ28Camaro]

Sorry guys to rehash an old thread but my holley 950 ultra hp is doing the exact same thing and I can't get answers as to why, even from holley, does anyone have the answer to why these carbs are flooding out from the primary bowl yet the fuel level in the bowl is sitting at about half the sight glass? Thanks

At what rpm is this happening?

[BlackoutSteve]

Did I miss what size needle & seats you have?
The larger the size, the less amount of fuel pressure will unseat them.
Wondering if this is the problem.
A typical .110 should hold closed 7 psi reliably.

Is the fuel pump mechanical by chance?

[pamotorman]

if it has a nitrophyl float try a brass one and make sure the spring is in place as the brass have a longer fulcrum arm giving more leverage to shut the N/S.

[John Wallace]

does anyone have the answer to why these carbs are flooding out from the primary bowl yet the fuel level in the bowl is sitting at about half the sight glass?

Shouldn't it be at the bottom of the sight glass?

[BrazilianZ28Camaro]

does anyone have the answer to why these carbs are flooding out from the primary bowl yet the fuel level in the bowl is sitting at about half the sight glass?

Shouldn't it be at the bottom of the sight glass?

From the Holley instruction sheet:

The fuel level in the clear sight glass should be mid-level for correct float adjustment

[flashgordon]

I have no idea how to post a video on here but I took a video with my phone tonight and I'm going to send it to the tech guys at holley that said it is physically impossible for this to happen, well I got it all on video, if anyone wants to see it I can email it to your address, it seems to happen after the car has warned up, I run a holley 110GPH mechanical pump and I have a Mallory dead head regulator witch I added, I used to not even run because the pump doesn't require a regulator and its turned down to 3 1/2 psi, float level just under half in the sight glass, blip the throttle e few times and it begins to vapor out of the primary overflow tube then it spits gas out and finally pukes gas everywhere killing the motor, I swapped the front and rear bowls completely as per holley tech and still same thing, the bowl never fills up when this happens but does start airating in the bowl

[JoePorting]

Replace the power valves. You probably have a hole in one of them from a back fire.

[JDR Performance]

Check your pm Flashgordon.

[Bob Hollinshead]

My Son had intermittent problems with viton tipped holley needle and seats for years that he could never figure out, it was random and couldn't be traced to dirt or O-ring problems. He changed to stainless a few years ago and hasn't had a problem since.

[flashgordon]

I've been lucky in the past with my 110gph manual holley pump running a small shot of NOS and my motor all on this one little pump, not sure if it's the problem but I'm going to install a Holley 150 hp pump and two regulators this weekend and see if it changes or fixes my problem, I will report back with the results, everyone on this forum has been very helpful, I appritiate all the information, I will put it to good use

[John Wallace]

From the Holley instruction sheet:

The fuel level in the clear sight glass should be mid-level for correct float adjustment

Do you have a copy of that?

This is what I usually go by.

Holley Float Level

[BrazilianZ28Camaro]

From the Holley instruction sheet:

The fuel level in the clear sight glass should be mid-level for correct float adjustment

Do you have a copy of that?

This is what I usually go by.

Holley Float Level

I think that's a little confusion John, the manual you posted here, (despite the fact its is for Holley HP )show the fuel bowls with sight plugs, probably from the older versions.

The Ultra HP (or actually Ultra XP) have sight plexiglass windowns , located lower than the old sight plugs, so you can easily set the fuel level at the middle of the glass diameter.

This is the file:

http://documents.holley.com/199r10565-1.pdf