292 fall down on acceleration
- Thread starter JimT
- Start date
Crankster
Well-known member
Hi Jim - a 6.5 is suitable in many if not most instances, for stock or stockish engines. This is what is provided with most carburetors and rebuild kits. If you live at high altitude, and/or have a performance cam in the engine the manifold vacuum will be lower under all operating conditions and a lower number power valve would be needed.
KULTULZ
Well-known member
That is referred to as TIP-IN HESITATION.
Usually (in this period car) it will be the accelerator pump (or adjustment), an overly lean fuel condition or vacuum/mechanical advance.
A POWER VALVE would usually show as a hesitation at speed whereas the valve does not enrich the mixture properly at speed.
Usually (in this period car) it will be the accelerator pump (or adjustment), an overly lean fuel condition or vacuum/mechanical advance.
A POWER VALVE would usually show as a hesitation at speed whereas the valve does not enrich the mixture properly at speed.
Crankster
Well-known member
292 fall down
We'll have to know more to help. I noticed a post from 2017 and others, talking about this, ignition timing problems, is this the same engine? Is this a recent thing or just started?
Have you given the engine a thorough Tune-Up? Compression test, vacuum test, ignition timing check, voltage checks? How do the spark plugs look?
It took me years to get mine running well, there's a lot more to a Tune-Up than throwing a few parts at it. Don't want to sound like I'm giving you a lecture, it's just this is well travelled road, I tried it. Practically everyone does, and guess what - it's a Dead End. Trust me!!
I have came to the conclusion the carburetor is sort of like the Angel on top of the Christmas tree or whatever. It's the last thing to mess with, not the first. Or icing on the cake maybe. Point being, there a gazillion things that will contribute to hesitation and stalling and poor running and fuel mileage and fouled plugs and the rest of it, but the carb itself always gets blamed first. I'm trying not to nag here, but it's always seems to be the same scenario.
Usually this is how it goes: Engine runs bad in Any Way = Replace Carburetor with 950 CFM 4 Barrel (ask me how I know)
I'm just telling you will pull your hair out trying to tune any carburetor (new or not) that is installed on an engine that has just about any other defects in basic setup and tuning, ignition timing, vacuum leaks, incorrect fuel pump pressure etc etc.
Maybe you've done all this stuff already, and everything is straight. Maybe your carburetor just needs a new internal accelerator pump, possibly somebody in the past left out a ball check valve, or something like that. Maybe.
There's no way for anybody here to know that.
We'll have to know more to help. I noticed a post from 2017 and others, talking about this, ignition timing problems, is this the same engine? Is this a recent thing or just started?
Have you given the engine a thorough Tune-Up? Compression test, vacuum test, ignition timing check, voltage checks? How do the spark plugs look?
It took me years to get mine running well, there's a lot more to a Tune-Up than throwing a few parts at it. Don't want to sound like I'm giving you a lecture, it's just this is well travelled road, I tried it. Practically everyone does, and guess what - it's a Dead End. Trust me!!
I have came to the conclusion the carburetor is sort of like the Angel on top of the Christmas tree or whatever. It's the last thing to mess with, not the first. Or icing on the cake maybe. Point being, there a gazillion things that will contribute to hesitation and stalling and poor running and fuel mileage and fouled plugs and the rest of it, but the carb itself always gets blamed first. I'm trying not to nag here, but it's always seems to be the same scenario.
Usually this is how it goes: Engine runs bad in Any Way = Replace Carburetor with 950 CFM 4 Barrel (ask me how I know)
I'm just telling you will pull your hair out trying to tune any carburetor (new or not) that is installed on an engine that has just about any other defects in basic setup and tuning, ignition timing, vacuum leaks, incorrect fuel pump pressure etc etc.
Maybe you've done all this stuff already, and everything is straight. Maybe your carburetor just needs a new internal accelerator pump, possibly somebody in the past left out a ball check valve, or something like that. Maybe.
There's no way for anybody here to know that.