Just fitted a Stromberg 81 to my Stock Model A engine. put it on a modified Weber intake sitting low paralel to the intake ports to keep the carb low so I can gravity feed it. Problem is that the gravity overcomes the float jet and fuel pisses out of the accelerator pump rod hole after a couple of minutes. Spoken to the Stromberg 97 people and ordered a new S-Jet assembly, but they tell me this is a common issue with gravity systems even on a new carb. Anyone got a solution? With the carb over the exhaust on an A I don't fancy the idea to to much fuel leaking out. Cheers Rich
Something would seem to be terribly wrong with the inlet valve. Is it normal steel pin, rubber tip, or mysterious 2-ball type?? If stock steel pin type, just unscrew it, clean, and reseat. Tapping lightly with a hammer in several rotation positions should get it seated, unless pin is badly grooved. It really should hold against the gravity head, which is very low pressure.
Your lucky Rich! There's so much silt in my tank it barely gravity feeds the stock updraft when the level is low...
The mention of silt in the Model A tank would make me think that your needle is not seating. Unless you had the tank taken out and cleaned and sealed, you are ALWAYS going to jet junk in your carbs with these old tanks. I just put a new needle and seat in my 81s and blew through it while raising and lowering the float, and the float should really stop the flow of gas through that needle and seat if it is working properly. Try putting a filter inbetween your carbs and your tank.
Check the float too....maybe the little tag is hitting the side of the bowl before the needle is closed, essentially letting in a small amount of fuel at all times.
You can put a few filters in inline just will still get in he carb and still leak Engine fires are very traditional!! Honest I'm not being mean If you run the line so the filter is lower than the carb that helps
Oh - I have! And when it starts missing, a quick change of filter cures it... As for Rich's problem? It's completely opposite to Tony Cardy's - his tank only gave enough head when it was full to overcome the 97's in his roadster and he had to fit a pump.
Better drain the gas out of your crankcase and put oil back in it while you're getting rid of the gravity tank setup that even cheap-ass Henry knew was a bomb waiting to happen on a down draft carb and didn't use after the Model A up draft...
Ford had to change the tank design in Mid 1931 because New York made it law that he couldn't sell cars in that state with a fuel fitting right above passenger's feet. That's the reason he adapted the late 31s for an indented firewall. to get the fuel fitting outside the passenger compartment. and in 32 went to the rear tank.
Cheers guys. It isn't silt getting in the valve as I haven't run it yet with this carb, the tank is cleaned and sealed ran fine with an updraft B carb. My 81 has been rebuilt but sitting for some time looks new inside. I checked the float in the 81 and it seemed fine, should get the New Grosse valve (s-jet) tomorrow and will try that. Rich
I'm new to this Stromberg stuff, but after rebuilding five of these things I have noticed that there are slight differences in float tangs, needles and inlets, with the wrong combo the float tang can end up bent at a relatively severe angle when setting the float level, thus puting more of an upward force on the needle causing it to bind in the inlet.
The new Stromberg ball valve should put an end to this problem, if it really was a problem. I just rebuilt three carbs with the new valves and hope they work fine (haven't tried them yet).
Guys The new S-jet ball valve seems to have done the job, it fires up idles and runs fine, with no leaks in my garage. Just need to fabricate a linkage to see how it drives. The engine note seems much smoother than the old B carb hopefully cause it is not running as rich. Rich
definitely put a shutoff valve between your carb and tank and shut the fuel off anytime you aren't using it. that carb will get a tiny piece of dirt in the valve and all the gas will leak out of the carb onto your engine/garage
thats one positive for having an updraft carb ....you wont fill the crankcase full of gas if it leaks.
I had a 81 rebuilt by one of the experts and it leaked on my "A" but the problem was he cross threaded the power valve and it wouldn't seat properly. Now I know how to repair a cross threaded power valve.
I have a shut-off and a sediment trap that seems to filter any silt. Issue I had with the updraft was no matter what I did to it, it used twice as much fuel as my 3/4 flathead on dual 94's ever used and at $10/gallon here I can't afford that. Want to be able to use the dam thing. Next question will be do I need to connect up the choke or will it fire up every time on a couple of pumps of the gas pedal like my flathead. Rich
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