BenzWorld Junior Member
Date registered: Sep 2006
Vehicle: 1971 280SL, 2007 R320CDI (White/Macadamia)
Location: Birmingham, AL & Pensacola, FL
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1971 220 Fuel System Issue
I have had "Brownie" for 38 years and this is the first time she has stumped me. I recently moved from Birmingham to Pensacola so I am without my independent mechanic that has maintained her all these years. About 10 years ago we replaced the worn-out Stromberg carb with a two barrel Weber that has given good service for a long time. For the last three years, Brownie has served as the backup car in Pensacola, where we keep our sailboat. So she is not a daily driver so I suspect that the carb may be loaded up with corrosion and crud. She starts fine, idles good, but she spits and sputters when accelerating. She will gradually build up speed as long as I don't create too much vacuum with the throttle. Depressing the accelerator to 1/2 to full throttle initiates the sputtering. She has an electric fuel pump mounted just outside the fuel tank and pushes the fuel to an inline filter adjacent to the old mechanical engine pump. I have noticed that upon shutting the engine off, the fuel runs from the carb back thru the filter to the tank. Is this normal?
The mechanic that installed the electric pump said that the pressure (I think about 4 psi) was sufficient to supply the Weber carb. The old Stromberg carb has a fuel return line to the tank. That line is no longer connected.
I have been gradually bringing her back to service. She has new plugs, wires, "hot-shot" electronic ignition, and coil. We have always set the timing at 5 degrees BTDC rather than the spec of 5 degrees after top dead center. She just runs and starts much better with that setting.
Any ideas on what my problem is? I am thinking of installing a new Weber carb but want to exhaust all other paths before I do that. I have sprayed some carb cleaner on the throttle valves and choke assembly and sprayed some of the cleaner into the carb IAW the direction on the can.