Holley bowls drain in about a week, leading to hard starting

Cougar Community Classic Cougar Maintenance Restoration and Repair
1

My car starts fine until about a week has passed, that is when I need to give it a bit of “Start ya Bastard!”

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IMG_42574032×3024 2.16 MB

The Previous carb (a 20-30 year old American 770 cfm Street Avenger) seemed to hold its fuel better. This carb. A Mexican Holley 670 cfm Brawler, drains, but I don’t smell fuel…

I thought the fuel pump has effectively got its own check valve, where does it go?

The 770 had cracked fuel bowls (blue silicone repaired) I am thinking of transferring the brawler sight glass bowls to the 770 and putting the old carb back on, am I likely to transfer the issue (or is it a metering block thing?)

Kind regards

John

2

Mine does the same thing, both with the Holley and the Edelbrock I used to run. I always assumed it was evaporating out the vent.

3

I’m not a holley fan (prefer the tuning capabilities of the Carter designed Edelbrock), but I’m assuming the configurations are similar. Yes, if left to sit for a while, the bowls will evaporate and dry out. This means you simply have to crank enough for the fuel pump to refill the bowls enough to then fire up. The vaporization is more rapid if you shut the car off when hot. One thing to help a little in this regard is to put an insulating spacer between the carb and the manifold (hood clearance depending). This generally bumps your torque up a touch as well based on testing from Engine Masters.

4

I have an air gap manifold and it’s winter… I get a month of sitting, but a week? Not smelling fuel, I only use 0% ethanol (98 Aussie octain, I think 91 US equivalent)

I am thinking of rebuilding the Street Avenger and swapping the Brawler glass window bowls onto the original carb. I guess I am wondering if the disappearing fuel might be meter/carb side or bowl side.

My carb experience is Webber & Varajet, I never had this issue on those carbs.

Thanks for your inputs.