Hello. I just replaced the 2 belts on my G4200 hst pto. I have the tensioner pulley on the outside of the belts. When I engage the pto, the tensioner pulley is presses towards the middle, thus tightening the belts. I feel like I have them installed correctly. My only concern is the drive belt from the engine continuously spins. Is this correct? When the pto is 'off' it feels like the belt is loose enough not to get hot. I followed the book and adjusted the spring to almost 3" when pto is engaged. Thanks
The above suggestions regarding the 'brake' are a good start. These 'brakes' are simply metal bits which keep the belt from jumping off the pulley when in the 'released' position. To replace the belts, you MUST remove a very long bolt which will not allow the belts to come off the lower pulley otherwise. (Bolt #30 on the parts-list
http://www.kubota.com/part/partsList.aspx)
I have a G5200 which is identical setup as yours. I am assuming you know these twin belts are METRIC length and should not be replaced with an "inch" length belt. ("Inch" belt would be either too short or too long to work properly) Also, the belts MUST be replaced as a "matched pair" lest one of them will be doing all the work whilst the other belt is only along for the ride.
Also, these belts should be 'wrapped' with kevlar and have 'fins' on the inside. The kevlar wrapping helps the belt to 'slide' when not engaged. The fins encourage airflow to improve cooling.
This is the set of belts I use ==>
http://www.usabearingsandbelts.com/m7/Kubota 66021-25080--kubota-66021-25080-v-belt-set-of-2.html
In any case, I am not sure what you mean by "the drive belt from the engine continuously spins"
If you are suggesting that one of the twin belts is still being driven by the engine and moving around the lower sheave when in the "released" position.... check and verify that the tensionor (idler) pulley is FULLY released from the belts. In my case, the cable which engages the idler was 'sticking' and not allowing the idler to retract from the belts.
When released, the idler pulley should NOT be touching the belts at all.