strange harmonics/vibrations

[washita]

well.... at 330 hours now I am pursuing an unusual vibration when accelerating motor to full throttle, never encountered this before. motor mounts are tight (first thing I checked) lovejoy couplers?

 

[MossRoad]

Does it only happen when the PTO is engaged and a mower deck is installed?

 

[washita]

no attachments are on the PT except for the pallet forks and the vibration occurs while parked

 

[woodlandfarms]

So, if you were to relieve the pressure on the PTO Pump, put a coupler across it, does it change the vibration? I guess I am getting at is how you get to wether it is like on a car... if you feel the issue under acceleration it is engine or tranny, and if you feel it under coast it is the wheels. Wondering if you can free-wheel your pumps, and see if the vibration continues. I would assume, probably incorrectly, that a pump with no load would have less chance of vibration than one under load.

 

[washita]

my neighbor feels that the vibration is a transition problem between low idle circuit jets to high flow jets in the carburetor, if I have time this weekend the pumps will be disconnected from the motor and motor ran to check for harsh vibrations through rpm range, if problem surfaces it will warrant a carb. rebuild