I dont know about your 2002. but on my 1999 the MMDC box gets a speedo reading from the two pitot tubes at the back of the boat.
If not winterized properly the water in the tubes will freeze. then when you put it in the water. the MMDC box will get water into it. and will cause the gauges to go crazy.
I have perfect pass with the paddle wheel so now I just leave the pitot tubes unhooked so no water is going to the MMDC box.
hope this helps.
"Let me not pray to be sheltered from dangers, but to be fearless when facing them."
1999 X-star, 330 LTR, Zero FLex tower.