Posted September 10, 2001 - 11:25 AM
01 WR426 Uncorked.
Posted September 10, 2001 - 01:04 PM
I was wondering if that unspent fuel is what causes backfiring. Think about it, blip the throttle quickly then let off, the pump is still squirting, so all that raw gas is still going somewhere. Maybe it could get through the throat somehow.
Posted September 10, 2001 - 02:36 PM
If you look at the way the pump operates releasing the throttle picks the rod back up off of the diaphragm, at which point the spring inside the pump will push the diaphragm back up, this will stop any additional fuel from being delivered and draw more fuel into the pump from the bowl.
To state it another way:
The arm that operates the pump is spring loaded, as the slide pulley rotates it allows the arm to push the rod and operate the pump, but when the pulley rotates back it will push the pump arm back into its starting position.
The popping at trailing throttle is almost always a lean idle circuit or leaky header.
Posted September 11, 2001 - 01:06 AM