Machine not reaching full spin speed.

one of two things, this is a newer machine and it doesn't work the same way as the older machines and ramp up to full spin speed, Everything is plastic for gears so they have to get much of the water out they can before hitting full speed. or second the belt is slipping. You didn't leave a model so I to a guess to how the machine really is.

Paul, if it has a clutch, yes. If belt drive, check tensioner and replace belt.

it could be a balance problem. Most machines are programmed to abort fast spin if the drum is unbalanced. This can be caused by too much in there, or possible the contents have clumped together somehow. Try a spin cycle only with an empty machine and see if it reaches full spin

It is still water in drum and pressure switch does't switch to empty position. After several attempt, washing-dryer go to end of program. See problem with drain out water.

Water drain until 1st level pressure switch EMPTY (3 min. timeout) + sequence
Dado

it may be any part of the balance mechanism under the machine..remember if you did not balance (level) it prior to installing, it has to self level on its own..this usually calls for some noise in the linkages when spinning..

Is the spin cycle reaching full spin speed or is it not spinning as fast as it should? If it isn't reaching full speed it could be caused by an uneven load (as this will stop some machines from spinning properly). Towels and items which get very heavy when wet can cause this.

Check plugs on motor assembly

It will not spin while washing, it's more of a rocking back and forth. As far as the spin cycle. If it's not reaching full speed I bet you'll notice that it's not doing the full cycle because the load is bouncing around and cause the washer to shut off. take some of the clothes out and watch it spin the water out.

You are right with your last comment. Laying the machine on its back is a no no. It allows the residue water in the bowl to possibly travel up the small plastic tube and enter into the water level sensor on the main (computer) control unit. It only takes a very small amount of water and it upsets the sensor so that the machine may not go through its cycle correctly. The water (depending on model) is extremely difficult or impossible to get out.
This may cause the machine to think that the bowl is not completely drained and so it will not go into full speed spin. Other problems may occur as well.
Bear in mind also that that a number of machine models do not go to full speed spin on a water temperature setting of warm or higher. When checking for high speed spin put your water temperature control down to cold / warm or cold.
Check also that your machine is sitting level ( the bowl is sitting centre in relation to the top shroud. If the bowl is leaning toward the rear of the machine when you look down into it, the ability to spin may be affected. There is a lever behind the bowl which activates a switch if the bowl comes in contact with it (when the wash load is out of balance) to stop the spin. The switch can also be activated when the machine is not level.
If your problem persists you may have to get a replacement main contol unit. If you are a little savey at technical things you may be able to get a discarded control unit from your local tip or recycler and recover the water level sensor for a change over. This may involve soldering though as well as precautions concerning stored electricity in the control unit capacitors and precautions about static electricity from your body or solder iron destroying other electronic components on the main control unit.
Hope this helps.

Its possible that the machine is not reaching full speed during spin. Check to see if the belt is slipping and that the thrust bearing pulley turns freely. When in the spin cycle the thrust bearing compresses the brake directly above it. If this brake is hanging up even a little the machine cannot reach full speed. The diagram on the right shows the thrust bearing assy. and brake.