The 7000 ?? you mean 700?
The sudden burst from 700 to 1000 could be a bad spark plug, a bad coil, the trigger has a bad connection,
a bad ground somewhere, the carbs not set right?
Does it run ok when running fast?
Had a problem with an intermittent miss, one wire from the trigger was broken under the shrink wrap/connector.
Do a compression test, test spark on each cylinder.
Change/check the diaphragms in both fuel pumps.
