I just bought a 22' scarab with a 7.4L Mercruiser MPI. The boat had fuel problems before, the electronic fuel pump filter was clogged up. I got that problem fixed, and now I have another problem, so I figured I would try this forum again because it was so helpful the first time. Anyway, the boat gets up on plain and runs for a short time and then all of a sudden, the thing just shuts down, like someone had turned the key off and won't restart, I was able to trace out that the ignition fuse was blown, so I changed it, tried it again, same thing. Put it on the trailer, hook some water up to it and it seems to run fine. I have had to be towed in 2 times in a row because of this problem. If anybody has any idea of why the fuse keeps blowing, please help me. It is a 20 amp fuse, and the fuse panel says it is supposed to be a 20 amp fuse for that switch. Any pointers would be appreciated.