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I've got a Holley 715 that I think has a problem with the vac secondary diaphragm. I installed a new diaphragm, and a new long yellow spring, but in actuating the arm up and down its readily aparent that there is no air movement, I just hear the diaphragm 'krinkling' up and down. If I take out the check ball I get air movement. I checked the Holley site for an exploded view to see if there should be a spring under the ball but it showed none.
With my other 2 Holleys I can open the primaries and actuate the secondary arm and hear air moving. I haven't cracked them open to see if there is a check ball in them or not.
If I'm looking at this right, with vacuum on it the check ball will be sucked tighter into the passage and allow no air movement and no secondaries opening?
So, should this be run with or without the check ball?
Thanks much!!
Jeff
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In the "old "days a check ball seat for a accelerator pump could be restored by "swaging" the old ball into it before replacing the ball, this smashed the seat surface to give a good seal, however, the ball in a holly secondary diaprham is not a check ball, it is there to slow and regulate the opening rate, there should be a tiny groove cut into the ball seat. If this groove is gone you must etch one into the seat. A metal scribe works well, don't worry about making it too big, but make sure it allows air flow, like you described, also helpful is a small amount of lube around the screw holes to keep the screws from wadding up the rubber diaphram. Of course you made sure the hole in the diaprham was indexed properly, so that is not oyur problem.
Just trying to be of assistance, not rude. Good luck, Scott W.
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Thanks for the info Scott!
I checked and there is a small groove in the seat. The other Holleys must not have the check ball installed. Guess all I can do is wait until the next time I take her out and see if the secondaries open.
Jeff
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Hey, I just remembered a way to test the secondary, with the diaprham housing assembled, but off the carb, compress the rod and hold your finger over the hole, first, if you can compress the rod into the housing the thing is working, second, if it stays compressed while you block the hole It does not leak! Scott W.
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suck on the hole and see if it moves and put tongue over hole to hold vacuum. gross but works. have a vacuum pump now but in old poorer days it worked :idea:
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suck on the hole and see if it moves and put tongue over hole to hold vacuum. gross but works. have a vacuum pump now but in old poorer days it worked :idea:
I actually did that :sqeyes: and it does work, so its back together with the check ball. I'll find out in two weeks if it works or not :( , next weekend I'm gonna take my CVX-18 to Glendo, Wy. to deliver her to her new owner. :squiggle: Gonna miss her alot, but I really love the jet!
