Holley 735

[lwg8tr0514]

Saw in the valleys of the intake...the dreaded fuel leak from the from bowl\accelerator pump.  Rebuilt with kit from Holley. Not a cheap Chinese kit.  Looked at accelerator pump cover for flatness and gently sanded completely flat...which usually works.  Rebuilt carb and around the gasket leaking worse and even began to leak when the pump was activated.  I took off car and as a stop gap, put black RTV around acc pump housing and that did fix the squirting around gasket upon throttle.  Looked this am after I brought car up to temp and looked for leaks. Actually sat there and watched for leaks...none. Only happens when the car comes up to temp and then cools down. Primary bowl emptying out.  I felt this am and wet around acc pump again and I think at metering block.  About to order a kits from Air Fuel Spark. and try this all over again.  I have been doing Holley rebuilds for 40 years and this carb giving me fits.  I am afraid either the body or bowl has a warpage in it. Anybody else have this problem after a rebuild?

[trotrof1]

Yes I did. It ended up being the pesky sealing washers on the bowl screws.

[lwg8tr0514]

I am never a fan of those nylon washers.  I do torque all the screws down to appropriate torque and did not over tighten.  I will try new bowl screws and new gaskets and maybe a dab of black rtv around washers and make it unnoticeable.  I am at the point with this thing of just throwing on my 750 DP and making a museum piece of the old 735. I even have an old 735 core with the lemans bowls.  A ultrasound cleaning and throw that on the DP.

[J_Speegle]

Nylon washers? Might try going back to the original style instead. Yes they shrink with age and non use but IMO sealed better.

[CSX4781]

The newer Holley accelerator pump diaphragm is a little thinner than the older ones. The screws that hold the pump housing to the bowl bottom out before the housing seals to the bowl. Not sure the current pump diaphragm from Holley are still having that problem but make sure the screws aren't bottoming out. Also might need to shorten the screws if you sanded any appreciable amount off the pump housing. Hope this helps.

Dave

[trotrof1]

Yes, use the OEM Holley washers. The nylon type seem to be better for the newer aluminum units.

[lwg8tr0514]

Solid advice here gents. 

[lwg8tr0514]

Here's hoping...



and the right screws(it has aftermarket hex style on now)

 

[JohnSlack]

After having rebuilt a Lemans Bowl 3259 with a Holley Kit and having the same results I can tell you that Drew's Kit from AFS made all of the difference when I went through the carburetor to fix the issues.

I won't use any other kits, end of story.

[pbf777]

Solid advice here gents. 

    DO NOT use "RTV" (or "most" any other of the "sealers" readily available at the auto-parts or hardware store) as these will most often prove soluble (in time) to fuel. 

    Scott.

[Drew Pojedinec]

Check very closely for hairline crack at the pump cover where the arm and pin is.
I have seen a tiny crack there and it opens up a tiny bit with throttle.

I've also seen trash in the pump cover screw holes that give a false torque.

I use fiber fuel bowl screws, I just rub vaseline into the paper and they seem pretty good to go. I'm not a fan of nylon gaskets.

Anything you need from me just ask, I'm around

[lwg8tr0514]

Check very closely for hairline crack at the pump cover where the arm and pin is.
I have seen a tiny crack there and it opens up a tiny bit with throttle.

I've also seen trash in the pump cover screw holes that give a false torque.

I use fiber fuel bowl screws, I just rub vaseline into the paper and they seem pretty good to go. I'm not a fan of nylon gaskets.

Anything you need from me just ask, I'm around

I got the kit from AFS with the paper bowl gaskets, I also got a new genuine Holley accelerator pump cover.  My GT 500 not concourse and I don't see a SAAC judge judging my to see if my accelerator pump cover is spec.  As an aside I  really like the content and knowledge of that guy over at AFS.  He hit a niche that no other guys I have seen hit. 60's Holleys.....

[lwg8tr0514]

Oh and I am suprised no one has said .... this whole topic is a sales pitch for Edelbrock carbs