RPM stands for Revolutions-Per-Minute, and is counted at the crankshaft. At 3000 RPM the engine is spinning twice as fast as at 1500 RPM.
3000 rpm is red line. Red line is about 3000 rpm,
Anywhere between 1500 and 2300 RPM, depending on how it's geared.
Mine did the same thing and shortly after my alternator had gone.
Check out the related links for information on the differences between .rpm and .deb packages.
1500 rpm.
3000 rpm or lower
An engine that vibrates at 3000 RPM has an issue with balance. The harmonic balancer or the crankshaft can become out of alignment.
1500
Normal is 20 to 40 psi at idle, 40 to 80 psi at 3000 rpm.
you need new plug wires
3000 RPM
54 at 3000 rpm