salty_waders

I'd like to get the choke working again on my Holley 4150. When the throttle is fully opened, the fast idle cam is not being pushed far enough to engage. I didnt see anything that can be adjusted to push it just a hair further?? New cam? Thanks!

INMYBLOOD

I don't have a choke on mine but here is a PDF I found on the subject.

http://www.holley.com/data/Products/...199R7948-5.pdf

salty_waders

Thanks for the reply but this article doesnt address my problem.

midyearvette

if it is a divorced choke, you can bend the rod for an adjustment
some models you can use a screwdriver to bend the tang that engages the fast idle cam
your question is really too vague to cover all the choke assy's...hope this helps

you may need to richen the spring if you have that type

QIK59

You say "working again" - did it work for you before ??
If so then what did you do to make it stop working ?

Fast idle cam should be rotated into correct position by the choke spring.

Re "new cam ?" - probably new choke spring thermostat is what you need.

salty_waders

Forgive my ignorance on the carb. I didnt play with the choke spring adjustment. I just noticed that when I fully open the throttle, it didnt push the fast idle cam enough to engage it.

I didnt know the choke spring would adjust the position of the cam? I thought the spring adjustment determined when the choke turns on and off?

JohnZ

Which carb is it - a 2818?

salty_waders

yessir 2818

QIK59

The choke spring "runs" the whole thing : choke and fast idle cam operation.
Full throttle actually disengages the fast idle cam - you've got it a$$ backwards

"Play with it" (hold the throttle partially open and move the choke spring) and observe - it's not very hard to figure out.

salty_waders

Again forgive my lack of knowledge on this subject but here is what I have: Engine is cold and the choke plate is fully closed. If throttle is fully opened the choke plate begins to open but fully closes upon release of the throttle. If I push down on the fast idle cam the choke plate "clicks" slightly open and remains open and the car will start fine and idle fast until I tap the throttle.

I tried adjusting the spring as recommended above with no luck. When the throttle is fully opened is the choke plate supposed to be pushed open and remain engaged barely open or should the choke plate "fall" open? Hard to explain but maybe someone can help.

QIK59

The question immediately above : choke motion is totally dependent on whether the motor is cold or warm respectively

With everything stone cold ;
you push the throttle down SLIGHTLY and the choke should close and the the choke side throttle linkage should rest on the fast idle cam.

If you fully open the throttle the choke should open slightly - 1/8" or so.

With engine warmed up;
If you fully open the throttle the choke should fall open.

With motor cold : what happens to the motor operation when you pump the gas a couple of times and start the car : Does it start okay and run on fast idle until you open the throttle and then it goes back to regular idle ?
AND does the choke gradually open up - watching it for 3-4 minutes or so ?

Jerry

midyearvette

on a cold engine, when you slightly tap the throttle, the choke should close tightly
when you open up the throttle all the way, the choke will unload a fraction of an inch
so, when you depress the pedal say half way, the choke should slam shut and activate the fast idle cam and adjustment, only on a cold mill.....hope this helps

salty_waders

If I pump the throttle a couple times the car starts fine but I have to hold the RPM up until warm. Its a convenience factor to get the choke working.

When the engine is cold, should the choke plate be completely closed with the throttle closed? Right now its completely closed when cold.

salty_waders

With a cold engine: the choke will open a fraction of an inch as described above, but will not stay open (unless I help it open, as if the throttle is not pushing the cam far enough).

QIK59

What happens if you don't hold the RPM up - does it load up (black smoke) - gradually run rougher and rougher and stall out ?
Or does it just slow down quickly and die ?

65 vette dude

My 2818 does the same thing, when I haven't driven the car for awhile. If I pump it once , the plate closes, and the motor fires, but quickly stalls like it is out of fuel. To get it started, I have to pump the throttle several more times, which opens the choke plate due to the release of the fast idle cam. Then it fires right up, but I have to keep it going with my foot until it warms up. I think the initial problem is a lack of fuel in the bowls from not being started for weeks, or maybe the fuel slowly drains over time from the pump, back into the tank.....or maybe a little of both. I believe the choke plate doesn't automatically close just because the motor is ice cold.......BUT, if your engine is cold, and you tap the throttle, then the choke plate will close, and rest on the fast idle cam.

salty_waders

quickly dies until warm...

QIK59

Okay now we are starting to get somewhere ! Some actual operational observation !

Check and confirm what is happening with the choke blade when this happens - sounds like the choke is falling open / opening to quickly.

If that is the case (choke falling open) you need to wind the choke adjustment (black cap) tighter to hold the choke closed with more spring pressure.

65 dude probably has a valid point regarding fuel bowls being empty.

Yes 65 dude the choke can not and does not close on it's own until you "release it" by opening the throttle.

midyearvette

the throttle does not push the fast idle cam open, to release the choke.....the fast idle cam is weighted and falls off as the choke warms up and the choke spring heats up and starts to release the choke
you may want to get into the choke housing and check the piston pull off for crud or a bad spring...just a thought

salty_waders

1. When the engine is cold, should the choke plate be fully closed? (mine is)

2. Then by fully depressing the throttle, the choke plate should slightly open (and stay slightly opened) right? ready to start and fast idle until warm or tapping the throttle? (mine doesnt)

thanks again for the help...