engine revs drop when driving off! kawasaki fh531v 18hp

[Larma 1]

Husqvarna R15t awd. Either the revs are too high but the revs drop significantly when driving off. it does slowly pick up again.
I've been moving the throttle plate up and down to find the right position, but no luck. After replacing the govenor seal, put back
together was slightly over revving. It then went into for a service and asked them to check the revs. Since it's return I noticed the revs
dropping when driving off. Quite low. govenor and shaft ok. maybe the govenor shaft isn't turning much under load?
any help would be great

 

[Larma 1]

Husqvarna R15t awd. Either the revs are too high but the revs drop significantly when driving off. it does slowly pick up again.
I've been moving the throttle plate up and down to find the right position, but no luck. After replacing the govenor seal, put back
together was slightly over revving. It then went into for a service and asked them to check the revs. Since it's return I noticed the revs
dropping when driving off. Quite low. govenor and shaft ok. maybe the govenor shaft isn't turning much under load?
any help would be great

 

[ILENGINE]

Was the static adjustment made on the governor after the seal replacement. And is the governor spring reconnected correctly.

 

[Larma 1]

the governor shaft turned fully counter clockwise, throttle on full/fully open.
governor arm rotated also counter clockwise. governor arm bolt re-tightend.
the spring is connected on the governor arm, I will double check the governor spring
on the throttle plate. I'll get back to confirm this.
kind regards

 

[Larma 1]

I think the governor shaft is stiff. the spring was hooked on ok but the tang was bent inwards slightly.
I straightened that. with the engine running and looking at the governor shaft I noticed it wasn't moving
when moving throttle back and forth. Using a long screwdriver I nudged it down and the revs dropped.
I did grease the new seal. I guess I can't do an accurate set up adjusting the throttle plate when the shaft
and governor arm don't move! I guess I'll remove the seal, get another one and use a drill bit to increase
the diameter just a fraction. To give it movement.
kind regards