Timing a motor by ear...

[dyeager535]

No, not in the tranny, but that would eliminate timing as the issue, since 3000RPM is 3000RPM to the distributor, regardless of gear. Out of gear vs. in gear will also tell you if it's fueling. If it was ignition related, it should happen at 3000RPM regardless of engine load.

Carb could certainly be a factor too.

 

[GsxrMike]

Well it only does it under load but I still think it could be ignition related because the engine blows right past 3000rpm when not under load and it only does it under load at full throttle. Does anybody know where I can get a tuning guide for an eddelbrock 1406 carb. (I think thats the number but I am at work so I am not for sure) It smells like it is running really rich. Sorry I didn't mention that before. I used to have the carb on a 305 in my old blazer and that thing screamed. (till it threw a rod)

 

[bp71k5]

How do you know the fuel pressure is ok? (i.e, Not too high or low?)

 

[GsxrMike]

How do you know the fuel pressure is ok? (i.e, Not too high or low?)

I checked it when I set the fuel pressure regulator (6psi I belive). Also if my carb was starving for fuel at 3000rpm there is no way it wouldn't starve at 5000rpm.

 

[TREA18]

Rene, mentioned the same problem and bad Accel wires that he replaced and know problems - posted on prior page - Hope it helps.

 

[GsxrMike]

Rene, mentioned the same problem and bad Accel wires that he replaced and know problems - posted on prior page - Hope it helps.

Yeah I had read that and thought about trying a new set of wires but I didn't figure a bad set of wires would cause this specfic problem at only one rpm range. I also have custom length wires that were put together by a redneck hill billy who was three sheets to the wind. Maybe I will try new wires after all.

 

[blackbitch]

Interesting conversation! Don't know what carb you have, but a "roundy round" friend of mine told me that my stumble was from the power valve linkage on my Q-jet being too loose. Took the slop out of it so that as soon as the throttle was moving, it was too. Put that together with 8* to 11* timing and has been no problem for the last ten years or more. Luck to ya.

 

[AZ79K5Project]

Does it happen only if you floor it? Do you have a Quadrajet? Maybe its the infamous quadrabog you're experiencing? It's just a matter of tuning the screw that tightens the secondary butterflies. I had that problem.

... friend of mine told me that my stumble was from the power valve linkage on my Q-jet being too loose. Took the slop out of it so that as soon as the throttle was moving, it was too. ...

I don't mean to hijack, but would either of you post up or shoot me a PM with additional info?

 

[original balzer]

Did you check out your mechanical advance springs and weights? Would also tend to sugest the secondary butterflys being too loose.

 

[GsxrMike]

Yeah the advance is good. Dizzy is newer msd unit. I am leaning more toward the carb now because she ran the same way with the initial timing at 18*, 14*, 12*, and 10*. I think I am running really rich but I don't know squat about eddy carbs. Guess I will hit google for a bit.

 

[GsxrMike]

In case anybody else needs it > http://www.edelbrock.com/automotive_new/mc/carbs_acc/pdf/carb_owners_manual.pdf

 

[4xcrazy]

i kinda skimmed through this, but i think i caught something saying you are running the Edelbrock 1406 carb?

if this is the case, you are decsribing to the T, exactly what i had happen a few times with mine.

I was trying for awhile to lean out the "rich smell" just like you are describing, while idling at least, in doing so, i rejetted the carb several times, different combinations, jets, rods springs whatever, tried to follow the chart to keep things in order and basically i would get a certain set of rods and jets where it would idle just fine, but under load it would start to stumble and stall out,,,like starving for fuel.

SO, i reinstalled the next set up, (rods/jets) and it got progressivly better until it doesn't stumble anymore, drives fine down the road, BUT still has a slight "rich smell" at idle.

i am thinkin this motor i have, at it's current configuration, would pass our emissions standards, IF i had Cats, an EGR valve and possibly an A.I.R. pump on it.

QUESTION NOW.
have you, or anybody else that you know of, tried rejetting this carb?

to me it sounds like the secondaries are too lean and starving under load and at higher RPM's.