What does the by pass valve do on the Stromberg carb? There is one on the front carb, but none on the back one. I replaced the diaphram becasue it was broken. I also replaced the hose connecting the device to the vacuum pipe because it leaked. By turning the screw on the cover I change the idle rate. Is there some way I should determine the best adjustment for the screw?

Thanks,

Charles Peterson
68 E-type, Seattle

Submitted by tubwhatif@aol.com on Sun, 08/14/2005 - 06:02

I have a 1968 4.2, That I attempted a simple tune up, that resulted in having my twin strombergs rebuilt as I wasn't getting fuel to the plugs. The timing in the books say 153624 which I timed to #6. It will only run if I flood it and then it seems to be running on only One cylinder. Are there different timing orders and what would cause the no fuel to the plugs problem? Fuel pump is working fine but its just not creating enough suction for the fuel to get to the plugs.

Submitted by cleavefamily@c… on Thu, 07/28/2005 - 15:47

Charles,
All the devices on the Strombergs are explained in Bentley's, The Complete E-type, which is available in the the JCNA Shoppe or Library page of this website. All of the devices attached to the carbs have one thing in common: they reduce emmissions under different operating condidions. As I recall the screw on the bypass valve is factory preset and should not be adjusted. It is correct on the earlier Variation 1 Series 2s to only have this valve on the front carb. Do not adjust idle by use of the screw on the bypass valve as you are only adjusting one carb. If this valve becomes out of adjustment it should be adjusted by taking CO2 readings at the exhaust and adjusting it to get the minimum CO2 at idle. Get Bentley's to do it right.
Stew Cleave
JOCO Chief Judge
\'69 E-Type 2+2 and other LBC\'s