Holley 3810 fuel drip booster

[Thomas W.]

I have 1967 327-300. I just installed the stock Holley 3810 to begin the spring season and engine flooded on start up. When I turned off the motor and looked down the carb throat I could see and hear fuel dripping from the primary boosters. I removed the carb and inspected the float, needle and seat and all seemed good. I checked the float for leaks and it checked out perfect. The float arm intersects needle properly. I tested the power valve is it tested good. To be safe, I replaced the needle and seat, re-checked the float setting and also replaced the power valve. I sprayed carb cleaner through the primary air bleeds. When I put the carb back on the engine the flooding condition and drip from the boosters was still the same as before. Then I removed the filler cap on the fuel tank and the condition still did not change. Not sure what could be causing this? I am using original Holley parts. Any ideas on what to do next would be appreciated. Thank you. Tom

[James G.]

Re: Holley 3810 fuel drip booster

Did you set the floats with fuel in the bowls?
There are at least 2 different length inlet float valves.

[Thomas W.]

Re: Holley 3810 fuel drip booster

With my 4160, the floats are set without fuel in the bowls. They are set about 1/4" from the top of the bowl then the bowl is attached to the metering block. BTW, I have an LT-1 also.

[James G.]

Re: Holley 3810 fuel drip booster

I was questioning whether it was a side hung float.
I just checked and 5/16 is spec. for the primary, the secondary spec is 11/32 -

See what happens if you push the primary down a little more- to a total of 5/16 - 11/32 AND move the secondary down to 11/32

[Thomas W.]

Re: Holley 3810 fuel drip booster

Thank you for the float set-up. My primary bowl drips until it is just about empty. I was thinking there was pressure in the system pulling the fuel through. Would the primary bowl empty of the float was just a little high? I am wondering if I have a particle stuck in one of the idle air bleeds.

[William F.]

Re: Holley 3810 fuel drip booster

You may have a pin hole leak in the float. Take float out and shake it. Can also put it in a pan of gas and see if it sinks. I had pin hole float leaks in 2 new Holleys.

[William F.]

Re: Holley 3810 fuel drip booster

Please tell us what you find out. These tech questions are most helpful when people give followup that may be useful to others with similar problems.

[Thomas W.]

Re: Holley 3810 fuel drip booster

Will do. Still working on the next steps.

[Thomas W.]

Re: Holley 3810 fuel drip booster

It took a while but I can confirm that my fuel problem was caused by a warped main body on the primary side. We determined this by looking at each side of the blue reusable gaskets. The gasket between the main body and the primary metering block had a portion displaying no impressions indicating it was not able to provide a seal on the main body side of the gasket. I have cured the leak buy using 2 gaskets back to back between the main body and the primary metering block. However, I am now in search of a List 3810 main body so I can get it right. My tech pros assume this condition is caused by the heat cycles over so many years especially sitting on the cast iron intake used on the 300hp motor. I have a December build date on my car, starting my search now. Thank you.

[Gerard F.]

Re: Holley 3810 fuel drip booster

Tom,

Don't throw the 3810 main body out. If it is just a slight warp of the meterng block surface (or base) it can be fixed by planing.

The first two photos are my Holley 3810 751 date code which I sent out to a machine shop:

MachinedSurfBottom (Large).jpg

MachinedSurfFront (Large).jpg

The two photos below are my Holley 3810 -763 date code where I planed the surfaces myself with 220 grit wet sandpaper over plate glass.

HolleyBodyFin-Surface-Planing (Large).jpg

Photo22-HolleyBodyFinishing 029Planing4 (Large).jpg

The last two photos are from my Holley Restoration Article in the Restorer Magazine in Spring 2011. If you would like a pdf copy of the draft of this article, send me a private message with your email address.

[Gerard F.]

Re: Holley 3810 fuel drip booster

Here's a link to a 2009 post on Holley Restoration Main body planing

https://www.forums.ncrs.org/showthre...ion#post449740

[Thomas W.]

Re: Holley 3810 fuel drip booster

Jerry, really good information. My friends did not think I could restore the surface to a flat condition. Now I will give it a try. Thanks.

[Ralph P.]

Re: Holley 3810 fuel drip booster

If you really want to do it right, get a "surface plate" (Look it Up ) .. Used in Machine shops to insure absolute flat surfaces for such purposes.