Why does spin cycle cut out before hitting max RPM?

Time for an engineer to look at it

Pump out time of 40 seconds sounds good.

No ND error code and you spin up to 850RPM which is max for the machine.

You have no standing water in the wash basket.... I'm scratching my head.

Could you do a Spin Only cycle with that same wet wash load and set the SPIN for Max Extract. After you start the Spin Only cycle put the machine in Service Mode and watch the RPM range. This cycle sets the display to 12 minutes. Let’s see if the wash load remains wet and what max RPM is reached.

""Maybe the pump is not turning on during the spin cycle?"" You have no standing water in the wash basket correct? I feel the pump is turning on or you would have standing water in the wash basket and the pressure switch would have never indicated an empty condition (Low Level pressure switch contacts) to the Control Board. The Control Board would have stopped the wash cycle with a ND for no drain error code.

The pump in the spin cycle will turn on a number of times see if you hear turn on in a Spin Only cycle

I just ran a Spin Only light wash load with about 5 gallons of water in the wash basket. Timer went to 12 min. I toggled into Service Mode to watch wash basket RPM. At about the 5 Min mark (toggle in and out of Service Mode) the wash basket reached 850RPM then a few minutes later it stepped down to 830RPM to end of Spin Only Cycle. You don’t have a water valve stuck open or you would flood/over flow of the machine. Did you here the drain pump turn on several times during the Spin Only cycle?
Rich

We are talking about FAV6800A or FAV9800A TL correct?
If so you need these links the Service Manual and parts look up; here is the Service Manual for reference. Sears Parts Direct for reference.
If your machine completes the wash cycle with no error code such as ND (No Drain) and there is no visible water in the bottom of the wash basket when you remove your wash load then I would do this test.
Take the next wet wash load that is dripping wet and lets do a Quick Spin Test in Service Mode. During this test test the FAV6800A LED display model will step thru the RPM (revolutions per minute) or goal is to ensure the machine will spin the wash basket up through all Spin Cycle RPM ranges. Any RPM range above 99RPM’s will be shown with a (.) dot after the two numbers displayed i.e. 350RPM will show as 35. 550RPM will shoe 55. And so on.
I’m and owner of the FAV6800A and I’m not sure what the LCD display of the FAV9800A will display.
Enter into Service Mode;
Page 14 of the Service Manual; below I have cut and paste the instructions.

Enter / Exit Service Mode
To enter Service Mode press the Enviro Plus and Spin Only keys (simultaneously) for three seconds or until the control beeps.
Now go to page 14 and enter this front panel key pad press to start a Quick Spin Test and see if the machine with that wet clothes load will spin the wash basket to 850RPM.
Quick Spin Test
While in Service Mode, press the Hand Wash
key to start a Quick Spin Test.
Quick Spin test steps are as follows:
1) Lock the lid.
2) Spin to index speed 90 rpm and hold for 60
seconds. Pump drains machine.
3) Spin to index speed 150 rpm and hold for 6
seconds.
4) Spin to index speed 350 rpm and hold for 6 seconds.
5) Spin to index speed 550 rpm and hold for 6 seconds.
6) Spin to index speed 700 rpm and hold for 6 seconds.
7) Spin to index speed 850 rpm and hold for 6 seconds.
Pump out.
8) Coast down to 0 rpm chimes 3 times.

Hit the Off button to get out of service mode.

If the machine spins the wash basket to 850 RPM then we need to start looking further. What are your results?

You can check the flow rate of the drain system by again entering Service Mode and turn the Drain Pump on in service mode. I would (hand fill) place 5 gallons of water in the machine and turn on the drain pump see page 16 for Board Output Test.

Enter Service Mode and press the Delicates key. You are now in Board Output Test now press the Presoak key and the Drain Pump will turn on. If your machine pumps out the 5 gallons of water in 60 seconds or less I would say your Sump Cap, drain line connection from Sump Cap to input to the Drain Pump, Drain Pump and discharge line are all working as designed. If the Machine takes greater then 60 seconds to dump the water then you need to start troubleshooting for a drain line restriction or Drain Pump issue…...Rich

Mine is doing it. What was your final result?

some lower cycles wont allow high speed spin, try heavy duty.

Bad/broken coupler/ http://www.davesrepair.com/DIYhelp/DIY285753.htm

ok guest you can set a fisher and paykel machine to skip one rince cycle so as to save water,

Most noises from a washing machine occur during the spin cycle. If you hear loud thumping during the spin, the load of clothes may have become unbalanced. Stop the washer and redistribute the clothes, then re-start it. Repeat these steps if necessary.

With the symptoms you describe i would suspect a intermittent heater element fault as you are getting earth leakage current which is tripping the whole supply rather than a current overload which would just trip the socket circuit breaker. Get the heating element checked over first as this is the most likely cause.

TRY REMOVING FRONT OF WASHER YOU WILL SEE 4 SHOCK LIKE PISTONS TAY GET DRY AND MAKE GRINDING NOISE OR SQUEEKS LUBERCATE ALL REAR HARD TO GET AT MAKE SURE YOU GET TOP AND BOTTOM (RAY)