Easy enough to try- next time instead of taking out the fuse, disconnect the battery and reconnect it. Will tell if maybe something not connecting with the fuse, which will be your easiest and cheapest fix. Prob not the fuse connection, but I have had on mine a cheap fuse that was thinner metal connectors, and it did give a similiar problem. I think it was a cheap 7.5 amp fuse somebody got at a dollar store. Never have I thought to look at the thickness of the connectors until that.
I've got a 98 sportster 1800, and to be honest, if it turns out to not be the fuse, and the battery disconnect proves to reset the mpem, which it will, I'd get a battery switch and be done with it to be honest. Wouldn't chance wearing out my fuse block for a $20 switch that isn't a bad idea to have anyway. I'm putting one on mine for safety due to the age of the boat. You can get ones that wire to a switch you can put on the console.
Maybe not what you wanted to hear, but I'd leave that MPEM alone as much as possible. To my knowledge any fault detected by the MPEM will deliver a beep, not a need for reset with no warning. I'll look at my manual tommorow to see if otherwise listed in the codes, but I assume you already did that.
Ha! Just thinking about the day I replaced the 7.5 fuse. I went to Oreilly and bought a pack. Came back and discovered the little fuse holders located on the top of the MPEM. Opened the boots, which even though 20 years old look like new rubber, no kidding. Opened them and there set what I feel sure were a complete set of factory fuses. Made me feel a little better about this project boat for sure
