lean surge

[timh]

I have 75Z w/355 sbc. My Edelbrock 600 recently started giving me a lean surge at cruise speeds. The fuel pressure is a constant 6psi. I have the Edelbrock A/F monitor and it reads between 12-13 (rich), but flickers off when the surge happens. I've adjusted the timing up and down, jetted the carb up one stage, then two stages, with no change. The fuel filter is 1 year old and is a purolator see-thru unit, it looks ok. There's no flat spots or hesitation during acceleration, just the lean surge at cruise. Any ideas??? Thanks, Tim

[Guest zfan]

Well my father had the same problem and could not get it to go away! He finally took me up on my near new edelbrock 750 sitting in garage and bolted it on and shazam no more problems.

 

Sorry guess that is not what you wanted to hear.

Just tellin what we went thru.

 

Mike

[Guest kc6wfs]

Check your float level, and condition of the floats.

 

Dave

[Guest Anonymous]

I have a 750 edelbrock on a 383 sbc in my PU/Z tow vehicle. My Carb was rich, but when I tried to lean in out it did the same thing (surge). Edelbrocks carb manual is quite intensive and their rich lean chart takes alot of brain cells to figure out. I think your metering rod springs are incorrect (too light or too strong I don't recall what makes it go lean) so that when you need part throttle enrichment on your primaries you dont get it; or your primary jet to rod size is to lean. I have a Excell spead sheet on the 750 rod to jet area ratio's and the percent delta from the stock setting. I could e-mail you a copy if you want it.