disclaimer, I don't own your machine so only answer from a theory point of view. If something is dragging or inhibiting "expected" current demand by the electric clutch it will tell the charging/bat system, "more current, please." That in turn can exceed the fuse capacity and open it. Someone recently has had a corroded or frozen clutch bearing problem which might do this, or something bent or fouling normal belting? And some of the guys here can probably tell you what the running current measurement should be. To hook up a DVM for current reading is a little tricky , but I think it could be done, carefully.
Otherwise the only thing I can think of is initial inrush current may somehow be lasting too long. (When the clutch first engages it wants more than 7.5 amps, but for how long?) There is is normally a delay in the fuse failure. Going to a larger fuse is probably not a good idea unless the mfgr made a mistake in the expected current value. With this I bet knowledgeable people will chime in.:laughing: