I've got a 3310-2 Holley DP on my car and, I've had a very bad off-idle dead spot. I finally got to it after spending all my time on other stuff, like the body, and what I found is that the accelerator pump rod isn't even moving. (Now forgive my ignorance here if I don't use proper terminology) I move the throttle and the accelerator rod does not budge. If I understand correctly, the only thing in there is a rubber diaphram and a spring, so I can't figure out what may be hung up. I've put a bit of rust penetrant on there, thinking maybe the pins may have rusted a bit but still no movement. If I push hard, I get a drop or two of fuel from the bottom of the pump housing. Can any of you Holley gurus supply some advice? Am I going to have to take it off and get a new pump?

Someone may have put the diaphragm in wrong. You need to take it apart and look at it. If you need help Pic's would help us to id the problem.

Don,
If something is clogged up in the pump circuit, it will not allow it to move as it cannot compress the fuel. Take the pump off and take a look, its just 4 screws.

I thought the 3310 holleys were vacume secondaries and not DP. If it has the housing on the passenger side of the carb and not an accelerator pump like on the front driver side of the carb then you would have to change the spring to a weaker one. The secondaries wont open on the carb unless there is a load on the motor to open them.

Take a look at the check valve under the squirter. They have a bad habit of sticking if the carb sets for very long.

Here (http://www.chevelles.com/showroom/DaDon/carb2.jpg) is a pic of the front driver's side of the carb. The lever in the front is what ain't moving. Bill, in order to take a look and get the housing off, does the carb need to come off or can it be taken off while on the car?

Don, you don't HAVE to take the carb off if you've got a right-angle screwdriver, but it will be a heck of a lot easier, take less time, and you won't run as big a risk of stripping the screws if you take the carb off.

If you need a hand or some extra parts, let me know.

Originally posted by DaDon:
I've got a 3310-2 Holley DP on my car and, I've had a very bad off-idle dead spot. I finally got to it after spending all my time on other stuff, like the body, and what I found is that the accelerator pump rod isn't even moving. (Now forgive my ignorance here if I don't use proper terminology) I move the throttle and the accelerator rod does not budge. If I understand correctly, the only thing in there is a rubber diaphram and a spring, so I can't figure out what may be hung up. I've put a bit of rust penetrant on there, thinking maybe the pins may have rusted a bit but still no movement. If I push hard, I get a drop or two of fuel from the bottom of the pump housing. Can any of you Holley gurus supply some advice? Am I going to have to take it off and get a new pump? Have you checked to see if the bowl gasket has the hole lined up with the accelerator pump channel?

Re-check your initial adjustment. If you have the spring-nut over-adjusted, you may have already taken all of the movement out of the lever.

It 'was' working properly when I first put it all together. Because I only pulled the car in and out of the garage, I really can't say when the problem started. I just noticed it within the last couple of months and, of course, now that I want to get it out on the street a bit. Though I haven't touched it since install, I'll check the spring nut. And Thanks for the offer, Xtreme. graemlins/thumbsup.gif I'm gonna figger this out!

Just let me know. Sounds like some crap got lodged and it just needs another good cleaning. Your spring nut looks adjusted close enough to at least work the arm...

I cannot tell from the picture, but the other thing to check is that the opposite end of the rod/lever from the spring nut rides on top of a shaft that rotates when the throttle is pressed. This is true for both accelerator pump levers. The shafts are designed with a cam or high area that operates the lever when the shaft rotates. If the arm operating the accelerator pump is on the under-side of the shaft , the accelerator pump lever will not operat. This is all mechanical linkage ... something has to move unless there is a serious bind and you should then feel some resistance in your accelerator linkage. So, check the placement of the arm that operates the accelerator pump. The end opposite the spring nut should be riding on top of the shaft operated by the accelerator linkage.

Well, I guess I'll have to bite the bullet and pull it off. Not that it's a big deal...I was just hoping there was a "use a bigger hammer" explanation. My knowledge of these carbs wouldn't fill a float bowl but, I guess this'll be a learning experience. Thanks for all the help guys. graemlins/beers.gif