I recently bought the holley fuel bowl that lets you change jets with bowl in place. I noticed a big difference in the accelerator pump between the stock bowl and the new bowl. The stock bowl has a hole drilled so the fuel goes into the accelerator pump cavity. There is also a check ball and a tiny metal bracket to hold the check ball in place. Then you have the spring, diaphram and the pump housing. The new bowl has 3 tiny holes between the fuel reservoir and the pump cavity. They give you a rubber plug that you insert into the middle hole which basically blocks fuel from going into the pump cavity. I had submerged the new bowl in water to test it and when you pump the accelerator pump nothing happens. What am I doing wrong, I dont see how this thing is supposed to function especially with the rubber plug there and I cant take it out because without the check ball the fuel will be forced back into the bowl. No there is no way to transfer metal bracket and check ball over to the new bowl. Someone with more experience please explain for me. Allen allioop108@aol.com
The old metal strap/metal ball-bearing check ball was replaced with the new-style rubber check valve many years ago. A worthwhile upgrade, it allows 1) faster, more responsive pump action; and 2) is replaceable unlike the metal ball and strap. Just like the metal ball style, the rubber valve is a one-way (check) valve. The rubber valve assures that the accelerator pump cavity will fill with fuel. One difference in operation between the rubber valve and the metal ball: with the metal ball, as soon as the accelerator pump arm pushes on the diaphragm, the ball is pushed upward and seals the openings allowing pressure to build in the pump chamber--the fuel squirts out into the main body, though the passages, and into the air stream. Unlike the metal ball, the rubber valve will LIGHTLY seal the pump chamber before you activate the accelerator pump lever. In fact, you must have slight vacuum in the pump chamber to allow fuel to flow into the chamber. It doesn't take much, and the accelerator pump spring, acting on the diaphragm makes sure that happens. Because the fuel inlet to the pump is already sealed, the accelerator pump is more responsive when the chamber is sealed with the rubber valve. Did you install the rubber plug so that the "umbrella" is on the bottom (pump chamber side?)
Thanks for a detailed answer. I had talked to the folks at tri state carburator (right down the road from me) and he was telling me the same thing. It had appeared to me that the rubber piece was just a plug and would not allow fuel into the pump cavity. Tir state gave me the same explanation and then showed me that it was indeed working (still had me bowl disconnected). I havent tried it as yet as I havent finished assembling the carb. And yes I installed the with the umbrella in the chamber side, tri state visually inspected that. Allen
