I live at 8100 ft

[speedo]

Fresh 2.4 with zeniths in a 71 softie. Engine is a stroked 2.2-2.4. Venturies are bumped from 2.7 to 2.85, mains are 130s and idles are 60s. Engine appears to be a bit lean, although I haven't checked the AFR. Coming back up the mountain, engine experiences a minor power loss...audible change in tone. My old school mechanic friend thinks the fuel pump is not delivering enough flow. We checked it at idle and it was about 66% of what it should be...but that was not really under load. He told me to bench test my other carb pumps to see what their flow numbers look like. I have always experienced that the Bosch pumps either work, or not...no middle ground. I bench tested two today...stuck the supply into a five gallon container, plumbed the feed to an empty oil quart container with ml gradations on the side. In 10 seconds I should be pushing 222mls. However, I got no flow through the feed, and spray from the return that was capped. I am not feeling confident that the pump is the problem. I would agree that I am lean, but wonder if I would be better off going to larger mains? BTW, in the engine compartment I do have a pressure gauge and that shows 3.5 PSI at static load.

Thoughts?

Speedo

[boxster03]

man that is a Grady question

[304065]

man that is a Grady question

In fact the late Dr. Ing. Grady Clay DID answer this question. . .

also see CHECK MEASURE ADJUST for details

http://forums.pelicanparts.com/porsc...-out-need.html

[speedo]

Looks like all those resources are MFI related. Unless I extrapolate...I am in the same "carb boat" I was before. My other carbed engines (weber) have not suffered this same dilemma. After talking with a couple fellow carb guys, I am still believing that the 009 pump delivers more PSI than is needed...thus the return line. Me thinks I need to check my AFR first. If lean...I know what to do. If not lean, plan B will emerge.

[304065]

do you have the little white book or the fwm?specs are in there for flow and pressure for the carb version of the electric pump

[Cornpanzer]

I hope I am understanding your problem...
When you climb to higher elevation, you will get a rich situation as air becomes more rarefied. If the pump is sufficient at the lower elevations, it wont be an issue at higher elevations since the engine is naturally going fat due to the lack of air. As you go higher, you need more air, not fuel.