Quick RAVE Test
I believe this is right, if not, someone correct it.
1. Remove the covers off the Rave valves
2. Start engine (take care around the clutch)
Both Valves should close
3. Remove clip and disconnect PTO side Solenoid harness above the PTO side Carb
Both Valves should float between full open and closed
4. Remove clip and disconnect MAG side Solenoid harness above the MAG side Carb
Both Valves should be Fully Open and not fluttering.
5. Put everything back together.
If on step 4 the valves flutter, there is most likely a leak. First place to check is the MAG side Solenoid. You will notice on the PTO side solenoid, a nipple that has no hose on it that is open to atmosphere. On the MAG side solenoid, the same nipple should have a hose on it. If not, put it back on. If it does, it is probably leaking, as the nipple outside diameter is smaller than the hose inside diameter. The clamp used deforms the hose into an oval shape causing a leak path.
To fix, remove that hose, put a small clear fuel line (or similar) that fits on the nipple tight, and put the hose you removed over it and use a new worm gear style clamp to seal it up.
This info and fix was found by others on Dootalk. I went through it and did the fix. I am in the process of taking pictures to post.
SB.