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 Post subject: Flooding Primaries
 Post Posted: Sat Feb 25, 2012 10:05 pm 
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Joined: Wed Jan 12, 2011 1:28 am
Posts: 140
Location: N.W.
Just redid a 9375 for my BBC and went to try it out. Electric pump, A2000, and Aeromotive prostock regulator. Was at 7.5, but I backed it down to 7. The float was set level to the bowl roof with the bowl off.

So when I run the pump to fill the bowls, once they're full it seems like the fuel pushes past the needle seat and I can see the primary butterflys being flooded with fuel. The secondaries seem fine, no issues.

With my 850 on the car (just a few days ago) it doesn't miss a beat. No issues with extra fuel pushing past.

I've removed the needle seat from the bowl and could try a new one, but the needle assemble appears OK.

Any suggestions?


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 Post subject: Re: Flooding Primaries
 Post Posted: Sat Feb 25, 2012 10:35 pm 
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Joined: Mon Oct 29, 2007 7:07 pm
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Location: Florida
Bad float, o-ring surface in the bowl corroded, float arm bent,,, Try using the 850 bowl on the Dominator.


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 Post subject: Re: Flooding Primaries
 Post Posted: Sat Feb 25, 2012 11:02 pm 
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Thanks Mark, I'll take a run at it tomorrow and see what happens.

Is there any point to just trying and new needle assemble, or is this going to be a process of elimination?


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 Post subject: Re: Flooding Primaries
 Post Posted: Sun Feb 26, 2012 8:54 am 
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Joined: Tue Apr 18, 2006 3:20 pm
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Location: Missouri
I've found the o-ring the cause of more leaking N&S than the actual N&S being bad. This is especially true if it was fine until after a minor float level adjustment.

Rick


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 Post subject: Re: Flooding Primaries
 Post Posted: Sun Feb 26, 2012 7:20 pm 
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OK, so I opened up the needle seat and float on the 850 bowl, and it looked just like the dominator one. So I put the 850 bowl on and was able to get an initial idle tune-up set. I'm going to replace the needle seat assembly and give the original bowl another try.


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 Post subject: Re: Flooding Primaries
 Post Posted: Sun Feb 26, 2012 8:47 pm 
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Joined: Wed Jan 28, 2009 10:58 am
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Location: South Carolina
Get a handful of 3/16" x 5/16" x 1/16" o-rings. I keep a bunch of spares in my jet kit box. No need to ever replace needle and seats. Just put on a new o-ring and go.

It's also nice to have some nylon N&S gaskets so they don't tear when adjustments are made.

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Matt
2011 Atlanta Dragway King of the Track


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 Post subject: Re: Flooding Primaries
 Post Posted: Fri Mar 02, 2012 4:12 pm 
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Joined: Wed Jan 12, 2011 1:28 am
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Location: N.W.
Little update... It was the o-ring, new needle assembly with new o-ring and all is good.

So when I had the carb off I decided to compare my original setup with what turned out to be the best driveway idle tune.

Its a older 9375;
I set the idle mix screws at 1 1/2 out and the transfer slots were showing about 0.020

After adjusting;
Idle mix screws at 2 turns out and the transfer slot on the primaries is at about 0.062 and the secondaries slot is covered up and not showing.

Does that seem odd?


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 Post subject: Re: Flooding Primaries
 Post Posted: Fri Mar 02, 2012 4:22 pm 
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Location: Adelaide Australia
J_6961 wrote:
After adjusting;
Idle mix screws at 2 turns out and the transfer slot on the primaries is at about 0.062 and the secondaries slot is covered up and not showing.

Does that seem odd?

When there set like that some engines will have trouble running the rear cylinders properly. Basically they dont get any fuel in the rear cylinders. If you have a tall enough plenum it can be OK but I dont know what you have. The better option is to open the secondaries and then close down the primaries and get your self to a situation where the blade opening areas are the same and the T-slots are the same etc. Then the air thats going down the secondaries has fuel with it and the rear cylinders maintain better heat for the snap of power. They respond faster if there already working is what Im getting at.


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 Post subject: Re: Flooding Primaries
 Post Posted: Fri Mar 02, 2012 6:30 pm 
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Location: N.W.
I'll run it again this weekend and try to make the adjustments, thanks.

This is a BBC with a victor jr. and an adapter for the dominator..... The 'funnel' approach.


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