New guy here, long time reader though. Holley double pumper sec. When you tighten down the cover on the diaphragm it stiffens up. I've switched diaphragms and tried the front cover on the back and had the same problem. I am not overtightening it because it gets hard before the screws are tight. Jester or anyone else ever run into this problem?

 

Whaddya mean gets stiff? The diaphram won't move when you work the pump, almost like something is blocking it from underneath? Did you put the spring back in under the diaphram?

If you answered yes to both, then you have a blockage somewhere either in the pump inlet or before the squirters. Possibly either the intake checkball is stuck, or the check ball/needle under the squiter is.

 

Yes to both questions. I'll take it off again and check the *****. Is there a spring behind them or just gravity, if gravity would I turn it upside down to check the one under the squirter?
:hail: Jester!

 

the inlet check valve is either a rubber diaphram or a ball held in place by this metal tab thingie depending on the model. The ball type are a bitch....if there isn't enough clearance between the tab and ball it won't open. Too much..and it won't close.

The outlet valve is pretty much always a needle that just sits in the space under the squirter screw. It gets stuck sometimes. once you pull off the float bowl and metering block....thats real easy to check. Just shove the carb cleaner straw in the pump passage (in the main body under where the metering block was) and spray. If it doesn't shoot out the squirter, you know it's blocked.

The intake valve is a little harder to check. I found the best way is to submerge the float bowl in the sink or bucket...with the open part facing upward, and the edge just above the water line. Use one hand to hold it there and work the pump, and the other to act and the outlet checkvalve. Make sure the pump actually pumps.

Kinda hard to describe....hope that helps.

 

It works! I think they were both stuck. I may have accidentily closed the gap on the inlet check ball when I rebuilt it. Needle was stuck until i did the cleaner straw trick, it finally shot out. The big die off is gone. Thanks.

 

Cool deal man. glad it worked for ya.