Stromberg 97 question
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Junior User
Joined: Feb 2012
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From: Monument, Colorado
Stromberg 97 question
Just installed a double intake, Stromberg 97s, on my 8BA engine. Got everything hooked up, with a new Holley fuel pressure regulator at approx 3.0 psi. Here's the problem: after I turn the engine off, for the next 10 minutes, all the fuel in the line (about 12 inches of line, times 2 lines) from the f.p. regulator forward, drains through the carb, and down the necks of the intake. I know this because the fuel lines are clear, I can hear the fuel dripping, and see the air bubbles coming up the lines from the carbs. Any advice??
Fleet Owner
Joined: Jul 2004
Posts: 27,299
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From: NM
I would guess the fuel in the bowls is vaporizing, which drops the floats, which lets all the gas in the lines drain into the carbs. Try setting the floats lower, and using double gaskets under the carbs to insulate them. Does your manifold have exhaust heating passages? I wouldn't think a dual manifold would. The aluminum manifolds really soak up heat from the block.
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Junior User
Joined: Feb 2012
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From: Monument, Colorado
Ross, I will try that advice, and get back to you. I set the floats at 1/2" down, like the manual shows. There is a LOT of bubbling, and noises going on also. The vaporizing idea is a pretty likely culprit. Thanks!!
Cargo Master
Joined: Aug 2010
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From: Houston
Ross nailed it. The gasoline with alcohol in it boils at a lower temperature and expands more when it gets hot. When I first rebuilt the Stromberg 97 on the 37 sedan it did exactly the same thing you experienced. I took the top off the carburetor, soaked up about half the gas in the float bowl, and cranked the engine with the ignition off (jumped the starter solenoid). This let me watch the fuel level attained from the fuel pump pressure (I run only the mechanical pump on that car). I set the float down three times in a row before I was happy with the fuel level. I think I dropped the float more than half an inch.
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Junior User
Joined: Feb 2012
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From: Monument, Colorado
Fred, thanks for the response! The float brings up another question. The Stromberg installation guide states I should have the gas level 1/2" (+/- 1/32") below the top of the carb body. Because I have an electric fuel pump, its easy to fill up and check. With this new situation, should I try to set the level lower (like 5/8" down, or more)?
Also, I was thinking of cutting a new base gasket out of 1/16" rubber gasket material (to insulate the carb from the intake, as Ross suggested). What do you think of that idea? The Stromberg guide says to not have one at all, which seems a little strange.....
Also, I was thinking of cutting a new base gasket out of 1/16" rubber gasket material (to insulate the carb from the intake, as Ross suggested). What do you think of that idea? The Stromberg guide says to not have one at all, which seems a little strange.....
Cargo Master
Joined: Aug 2010
Posts: 2,927
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From: Houston
I didn't set the fuel level much lower than spec, I just had to lower the float a lot to get the correct fuel level.
My favorite insulator is a stack of carburetor to intake gaskets. Lots of the flathead intakes have studs long enough to take extra gaskets. I would not use rubber gasket material since gasoline will probably attack it and makes a gummy mess.
My favorite insulator is a stack of carburetor to intake gaskets. Lots of the flathead intakes have studs long enough to take extra gaskets. I would not use rubber gasket material since gasoline will probably attack it and makes a gummy mess.
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