Technical 1936 Ford flathead V8 carb issues

Hi. Recently purchased a '36 Ford coupe-ute (fairly uniq ue to Australia - Canadian built). Very original, although it has a later '39 24-stud V8. Carb is the Holley-94. Hard to start, stumbling, stalling etc., although once cruising at 50mph, it's fine. Put a kit through it. Full of dirt - one jet blocked. Eventually started up and idled ok, although the idled surged a little. Worrying thing is that it still ran with both needles screwed all the way in. Not sure if my needles are damaged - they're a little round on the tips, rather than sharp points. I didn't bottom them out hard. Could it be that fuel is getting through somewhere else at idle? Also running an electric fuel pump (3-4.5psi / 114litres/hr - and regulated down to 2.5psi). Any experience with this?

 

Since it was "full of dirt", it is likely that some passage is still blocked. It probably needs to come apart again and all parts fully cleaned. Also, the power valve may be leaking. Most new power valves do not seat properly in the old 94 castings. The radius is too large and the valve will not fully seat. There will be a constant leakage at the power valve if it is not seated in the well.

 

Easy to check power valve. Remove carb, set on the bench and see if fuel leaks out. Another check is to look down the carb throats at idle and see if any fuel is flowing.

 

Have you now installed a fuel filter before the pump?

 

What is your location ? If we know this, someone local may be able to help you.

 

Another added tidbit.
If you tighten your idle screws and don’t see any rpm difference. It is normally because you have a vacuum leak.
The power valves come into play when the vacuum reaches a higher rpm off idle. They are not designed to open at idle. The carbs venturi vacuum port should be plugged on your later 39 engine since it doesn’t use the later 8ba loadamatic distributor .
Yes many of the new power valves have a sealing issue that could cause your vac leak.
I’d suggest since this is your first rodeo that you send your carb to a well establish rebuilder who knows those carbs.

 

Thanks. Sorry for being slow to respond. I thought I got email alerts. I've just replaced the fuel filter before the carburettor. I also decided to bypass the mechanical fuel pump altogether - just to remove another variable. I've been trying to locate a decent adjustable fuel regulator so I can wind the pressure down - I'm guessing the pressure is too high and it's pushing the needle open and flooding the bowl. And nickthebandit asked where I am - I'm in Fremantle, Western Australia. Cheers! PS Also replacing timing cover - but I'll do a separate post on that.