Before I call Uncle Max up. I was just wondering if any of you out there had this problem . The Stromberg is completely overhauled 81 from Uncle Max. Its on my 4 banger RPU. I have a electric fuel pump set at 1 1/2 lbs. pressure and regulator. It runs real good and strong ,idles good. No leaks when driving. But then when I shut it off , let it sit for a few hours or the next day. There is drips coming from the throttle shaft and dripping on the frame. I don't know if something is not closing completely and letting gas buy! I am going to try to shut the gas off and shut the fuel pump off . And let it run a little longer before I turn the key off. I will see if that makes any difference. I was just curious if any body else had a similar problem . Thanks for your time. Bob................
If I recall correctly, Clive from Stromberg had said once in a thread here somewhere that one should always run a return line back to the tank from the fuel regulator to siphon off gas and avoid what you are referencing. Others may have a different light on the subject.
I'm using the original Model A fuel tank. I don't know where I would run a line back into it really. Because I only have the one steel line coming out of the bottom of the tank, into the glass bowl on the fire wall. I understand what your saying vtwhead. I'll see if I can find that thread. Thanks vtwhead for responding. Bob.....
Here's another thread on the subject .. https://www.jalopyjournal.com/forum/threads/how-to-stop-stromberg-97s-from-leaking.832239/
Another option would be to install a separate cut off switch for your fuel pump. Flip the switch on the pump first before shutting down the engine which would lower your fuel pressure.
That's what I have Pete. That's what I did last night. I shut the fuel pump off and shut the fuel tank shut off, off. And let it run a little and then shut the engine down. I didn't check it yet this morning.
If you are using the original Model A tank I would imagine you have a good bit of pressure coming from it, any return line would be open to that pressure. Didn't thye have a petcock as part of the sediment bowl? Thats what I'd be turning off. I assume Max used the ballbearing type needle & seat, but it's best to confirm it. I'd think they'd seal at that low a pressure.
Yes, is the tank higher than the carb? If so, the gas is seeping past the needle due to the pressure of the gas in the tank. Does the stock A shutoff valve still work?
I do shut the shutoff valve off all the time. Its under the gas tank. The fuel line from the sediment bowl goes down to the electric fuel pump along the frame rail. Then it goes back up to the regulator. And from there it goes to the middle carb. Only running the middle one for now. Here is a picture of what I have. Bob.........
I dealt with Clive over at Stromberg for quite a bit on this very issue. The problem is indeed resolved by installing a return line back to the tank or a fuel shut off valve. Just need inlet fuel pressure to drop to 0 soon after shutdown or the level rises and causes a leak out the throttle shafts. It is probably better to point you to this lengthy thread on the problem which includes some videos showing the rising fuel level after motor shutdown. https://www.jalopyjournal.com/forum/threads/dripping-stromberg-97s-after-motor-shutdown.1013921/ Best of luck!
Thank you sir. I will read that thread. I don't know how I could run a return line back into the tank. I am using the original tank. Appreciate it. Bob.............
for anyone else suffering from this issue the key is that the return line needs to have a .024-.028 restrictor inside... From that thread... Norm's suggestion is a return line to the tank which contains a .024-.028 restrictor. This is large enough to allow sufficient gas back to the tanks to bring the residual fuel pressure down in a matter of seconds but not so large as to reduce the working fuel pressure. By eliminating the residual fuel pressure quickly this will mean VERY little rise in the fuel level in the bowl. Hope that helps.
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