The fuel gauge on the 800 started acting up the last few times I was out. Now the top two bars don't light up when the tank is full but other than that it seems to be pretty accurate. I did a search and found one thread but it was locked down so any ideas??

You should be able to read a locked thread, you just can't post to it. I'd say the fuel sending unit isn't working properly or something is stopping the float from rising as far as it should.