Am I too Rich or Lean?

[mally002]

Hey Fella's,

Took the 240 out today and she was running great for a while, however as the day progressed I noticed that once I hit 4,000 rpm's it wanted to bog down and not give me all she had.

Below 4k rpm's it seems fine (although maybe not pulling as strong as it should).

Would this be a symptom of being to rich or lean? It ran like this once before and my mechanic said he adjusted the carbs but not sure if he meant he adjusted for lean or rich (and he is long gone).

Thanks,

Randy

[Gary in NJ]

Next time you experience this problem, give a pull on the choke lever. If the problem improves; you are too lean. If it gets worse, you're too rich.

[JLPurcell]

You could also pull your spark plugs and take a read. White-lean, Black-rich, you want a nice light reddish brown. jlp

[d240zx2]

According to my wife, one can never be too rich....

But the above advice is good.

[240260280z]

Sometimes bad points causes high rpm bog that seems like fuel delivery problem.

[mally002]

AS always.......Thank you gentleman for the advice.

One day (heck who we kidding) I'll learn to be a better mechanic..........

Loved the too rich comment, my wife would have the same thought.

PS.....pulled the choke back, it got worse. Should I attempt to lean these out by small turns on each carb, or just find a mechanic. Wasn't sure if they need to be sync'd after they are leaned. Or if ya'll have a better "shade tree" approach let me know.

PSS.....Blue, got rid of the points and upgraded to PerTronix.

Edited May 20, 2011 by mally002

[motorman7]

PSS.....Blue, got rid of the points and upgraded to PerTronix.

That might be your problem right there. Petronix did not work well for me, though it has for others. My Petronix would miss above 4K RPM on my motor. Swapped it out for a 280zx dizzy and motor works wonderfully. I will stick with it.

[JLPurcell]

That might be your problem right there. Petronix did not work well for me, though it has for others. My Petronix would miss above 4K RPM on my motor. Swapped it out for a 280zx dizzy and motor works wonderfully. I will stick with it.

It seems like I have read a lot of negative experiences of members using the Petronix set up. jlp

[d240zx2]

Unless something untoward happens, I'll be singing the praises of Pertronix for quite a while. The installation of that simple system literally woke-up my Z. Way-easier starting, revs to 7K without a hitch. I'm one VERY satisfied customer!

[JLPurcell]

Back in the day I used the stock distributor on my 72, removed the vacuum advance and set it up to the specs in the How To Modify text. I installed headers, Mikuni 44's and was competitive in prepared class. Now for the 70 the last setup for it was a MSDS system firing off of the flywheel. Both were effective. jlp

[Gary in NJ]

PS.....pulled the choke back, it got worse. Should I attempt to lean these out by small turns on each carb, or just find a mechanic. Wasn't sure if they need to be sync'd after they are leaned. Or if ya'll have a better "shade tree" approach let me know.

In my opinion, anytime you make a change to the mixture, you should re-sync the carbs. A 1/4 turn on one carb does not necessarily translate into a 1/4 turn on the other.

[JLPurcell]

In my opinion, anytime you make a change to the mixture, you should re-sync the carbs. A 1/4 turn on one carb does not necessarily translate into a 1/4 turn on the other.

ditto!