Quote:
Originally Posted by OsoMoore
Control Pressure #1
Engine off, FP running, gauge valve OPEN, engine cold
1.0 Bar
Control Pressure #2
Engine running, gauge valve OPEN, immediately after first engine start of the day
1.3 Bar
At this point the engine idled on its own. However within about a minute it started losing RPM and wanted to stall. I held the throttle open by hand.
Control Pressure #3
Engine running, gauge valve OPEN, after about 6-7 minutes running
2.3 Bar
While approaching this #3 reading, I occasionally revved the engine. The control pressure would rise to around 3.0 Bar when I revved. Whilst changing hands to hold the throttle open, the throttle closed some and dropped to about 600 RPM. Although I opened it back up right away, it seemed to be no longer firing properly, and would vibrate the engine. I got the RPM to raise up to about 1500 RPM, but the idle never smoothed out. Within about a minute, I was no longer able to keep RPM up and it stalled. Then it would not start. This is typical behavior I am experiencing.
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Yes, the control pressure is a little low when cold, i.e. it should be 1.5, and higher
when fully warm (3.3) resulting in the mixture now being a too rich. You should be able
compensate for this by leaning the mixture with mixture screw temporarily at a constant
RPM to keep it running. The engine, though, won't accelerate properly but your test
at this point is to see if you can keep the engine running and eliminate the CDI unit
as a potential source of your problems. You can also move the sensor plate arm
to lean the mixture when you think it's going to die to keep it running temporarily.
To lean the mixture by increasing the control pressure, you can lightly tap on the round
pin on the WUR. As you lightly tap on the pin, monitor how the control pressure changes
when cold. If you tap too hard, the WUR must be disassembled to re-position the pin
so be careful.
Make sure that you have power coming to the WUR (gets power when the FP runs)
or the control pressure will not increase properly as the engine warms. The WUR
does warm-up from the engine case as the engine warms, but not enough unless
the ambient/engine is really hot.