PHF32 Accelerator Pump REPAIRED OK 860GT

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Tinkerbell
Mariana
Posts: 48
Joined: Sat Sep 05, 2020 3:57 am

PHF32 Accelerator Pump REPAIRED OK 860GT

Post by Tinkerbell »

Hi All,
I was able to repair the non pumping accelerator pump by replacing the upper check valve. I primed the pump and now it pumps well. The defect in the check valve is difficult to troubleshoot except by replacement. I took Steve's advice and primed the hole in the top of the pump with a glass eyedropper purloined from my heroin kit, and then put my finger over the hole and worked the pump plunger. I got some pumping where there was none. This told me that the lower check valve was probably OK, because if I primed the pump and reinstalled the upper valve, I got nothing again.
I drilled out the brass plug in the old valve and inspected the plastic ball under magnification. Both the spring and the seat had left very tiny impressions on the ball after 45 years. When I first got the check valve out of the carb and poked it with a toothpick, it made a slight click , one time. I assumed it was gunk or varnish and it would clean up OK. What I think was going on is that the plastic deformed into a shallow neck that was just enough to jam in the through diameter of the seat and increase its resistance to being dislodged.
I could not blow through the old valve as a test and this was true for the new valve as well. One online commentator said that he replaces that valve as a matter of course during a rebuild, since it is difficult to test them.
Sincerely,
Kara
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