Is there a way to test a Power valve in a carb WITHOUT taking the carb apart?

Nope. Take the PV out and suck it closed and see if it holds.

I cant see how I could use my Mighty-Vac to test it at a certain vaccum. All I know is the go/no-go test.

Nope. Take the PV out and suck it closed and see if it holds.

I cant see how I could use my Mighty-Vac to test it at a certain vaccum. All I know is the go/no-go test.

I was afraid of that...I just HATE the thought of taking apart a pretty much brand new carb. for possibly nothing.

I alway thought if you could turn the mixture screws in all the way closed and the engine still runs=blown PV. I KNOW the transfer slots are squared off.

Well I changed the power valve & it seems the old WAS blown!
Car idles MUCH cleaner now & even had a lean POP since I had the mixture screws(4) only out 3/4 of a turn.

I KNEW I read this somewhere......from the Holley website.

Most of the popular Holley “Street Legal” and “Street
Performance” carburetors incorporate a power valve blow-out
protection system. A special check valve is located in the throttle
body expressly for this purpose. This check valve is
designed to be normally open but will quickly seat to close off
the internal vacuum passage when a backfire occurs. Once
closed, the check valve interrupts the pressure wave caused by
the backfire, thus protecting the power valve.
If you have a carburetor older than 1992 (or you have experienced
an extreme backfire) and expect a blown power valve,
use this simple test. TEST: At idle turn your idle mixture screws
(found on the side of the metering block) all the way in. If your
engine dies the power valve is not blown.

I KNEW I read this somewhere......from the Holley website.

Most of the popular Holley “Street Legal” and “Street
Performance” carburetors incorporate a power valve blow-out
protection system. A special check valve is located in the throttle
body expressly for this purpose. This check valve is
designed to be normally open but will quickly seat to close off
the internal vacuum passage when a backfire occurs. Once
closed, the check valve interrupts the pressure wave caused by
the backfire, thus protecting the power valve.
If you have a carburetor older than 1992 (or you have experienced
an extreme backfire) and expect a blown power valve,
use this simple test. TEST: At idle turn your idle mixture screws
(found on the side of the metering block) all the way in. If your
engine dies the power valve is not blown.
You can install a anti backfire power valve saver on a carb not equipped with it.You drill and tap the vacume hole and it screws in.Its a check ball.

You can install a anti backfire power valve saver on a carb not equipped with it.You drill and tap the vacume hole and it screws in.Its a check ball.

My 0-82751 HAS the valve in it but 6 or 7 violent backfires still blew the PV.
all set now & running awesome.

not always ........... but a good percentage of the time a blown PW will cause a surge at idle not to mention a very rich condition that appeared suddenly

not always ........... but a good percentage of the time a blown PW will cause a surge at idle not to mention a very rich condition that appeared suddenly

yep ALL of that............

http://www.youtube.com/watch?v=UY2-58gMlBc

yep ALL of that............

http://www.youtube.com/watch?v=UY2-58gMlBc

the part that gets me is ............ spending HOURS trying to tune it out l:)

till it sinks in that's whats wrong ............:clonk:

please don't ask how I figured that out the first time ;)

the part that gets me is ............ spending HOURS trying to tune it out l:)

till it sinks in that's whats wrong ............:clonk:

please don't ask how I figured that out the first time ;)

I only spent time trying to tune it out because everyone including Holley tech was telling me the 'the new carbs have a blowout protector so your PV is fine'!

My gut was telling me otherwise.:yes:

I only spent time trying to tune it out because everyone including Holley tech was telling me the 'the new carbs have a blowout protector so your PV is fine'!

My gut was telling me otherwise.:yes:

yes I talked with the "experts" at holley's help line :rolleyes:

bottom line IMO ....... if car backfire's & then doesn't idle correctly & you're smelling rich ;)

put your money the P.V. :thumbsup:

Sounds awesome!:thumbsup:

Music to my ears.:yes: