PTO Engagement Not Smooth

C

Cut up

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2016 48” Scag Tiger Cat II
M/N STC II-48V-23CV, S/N 8900144 with a Kohler M/N KT740-3042 S/N 4601500684.
The mower has a rough life due to the way previous owners had worked on it. 3 of the five deck pulleys were badly bent, the PTO had been pounded on with a hammer, the original engine had been replaced with a different engine and the mower had obviously been parked outside in the elements for a long time.
I replaced the PTO with an 8TEN PTO, I replaced all 3 spindles and all the deck pulleys, new blades and belts also with 8TEN parts. I checked the air gap before installing, burnished the clutch as per installation instructions. When I engage the PTO the engagement is not smooth, the deck shutters one time when engaged but is smooth once it’s at speed which is almost immediately. I’ve tried it at full throttle, 3/4 throttle and 1/2 throttle.
Is this characteristic of a new PTO?
 
Hello C.,

8-TEN parts have been good for everything that I have used them for. Remove the deck belt and verify there is no dragging or a pulley that did not seat properly when tightened.

You would need an Amp clamp to verify the pull/hold in coil draw, but I don't think this is an actual clutch problem.

Verify all of the grounds are actually clean and tight. Just looking at them does very little good.

Other than that, there may be some deck belt whip action going on during the initial deck engagement.

Give it a good mowing break-in run and see if all the new parts get better acquainted with the existing.

Be sure to check the engine mount bolts to make sure they are tight and seated. I've found way too many DIY jobs that had missing or loose hardware.
 
Thanks for your response Lawn Addict.
After 1 hour of use, with belts off all spindles spin freely an all spindle pulleys are secure. The 4 engine bolts are secure.
What would cause belt whip action?
 
Hello C.,

The initial belt whip action is typically caused by the belt initially gaining a full grip on the pullies until they gain full RPM. It also happens if the engine running speed is too low and putting an extra strain on the engine. The deck should always be engaged with the engine at maximum RPM.
 
Would it be safe to say that, “there is a approximate time for new belt break in” for belt whip action to stop?
 
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