Hey all,

Getting the car geared up for the season and came across an issue with my Holley 650 DP - the secondaries aren't shooting any gas. I took the car up the road and back and tried to get on it a couple times and noticed it had no power and was lean. I came back, popped off the air cleaner, and pumped the secondary pump by hand - no gas out of the nozzles. I checked the float level and I get gas out of the bowl with a pretty good bump of the car. The car has been ran a few times during some nice days during winter here and it ran fine. This is the first time it's happened. Any ideas?

PS. Forgot to mention, if I give the carb a love tap or two while pumping the secondary pump, I get a little misty squirt or two out of both nozzles, but nothing steady.

 

Sounds like it's time for a disassembly, cleaning, and kit install.

 

I was thinking the same. Any idea what part number rebuild kit fits this carb?

 

http://www.summitracing.com/parts/HLY-37-485/

 

If you want to try and save time and money... Pull the screw out that holds the discharge nozzle out. Pull the nozzle as well. There is a little check valve under where the screw was - if you can remove it with a paperclip, great. check for cleanliness - put your finger over the hole and pump the carb.. anything? Spray a little carb cleaner down the hole if you have some and reassemble those parts.

No squirt still, right? Take the carb off the motor and flip it upside down, watch out because gas will come out. Take the 4 screws off of the rear accelerator pump housing and carefully remove the diaphragm underneath. There is either a ball or a rubber check valve below here. If it is rubber it may need replacement - at the very least make sure it is clean on the underside. If it is the ball, get a can of carb cleaner and make sure it moves smoothly. If you don't replace the diaphragm on reassembly you will want to keep an eye out for leaks.

If nothing still, it sounds like you have blocked passages. Have fun.

 

Thanks for the help! It turned out to be the rubber diaphragm that is orange and circular under the pump diaphragm housing. I replaced both the rubber piece and the diaphragm housing - it is working great now!

 

sweet. I was going to mention that I believe the accelerator pump diaphragm and check valve are available from the "Help!" line of parts at Autozone and such.

have fun!