Mechanic help please?

Hello everyone I'm no mechanic but this sounds like something I may attempt to tackle if I only had a clue as where to start. My dad has a 2000 model Johnson 40 hp 2 stroke engine. Since he purchased it used about 3 months ago he had a new ignition switch installed and now when he tries to start the engine he is blowing a 15 amp fuse inside the engine cover. He is also getting an alarm when starting and oil light and a hot light oil level is good . This sound like an electrical issue to me, but like I said I'm no mechanic. Any help is greatly appreciated.

sounds to me like a wire is crossed on the ignition switch

Sorry, after speaking with him he now tells me that it was doing this before the new ignition switch.

Check your service manual. That fuse has always been a 20 smpere fuse.

If the fuse DOES NOT blow when you simply turn the key to the ON position BUT DOES BLOW when the key is turned to the START position, then obviously the short is in the starter circuit.

Check the color of the wire attached to the "S" terminal of the ignition switch. That same color wire should be connected to one of the small 3/8" nut terminals of the starter solenoid (check it).

If the wire is correct, remove it from that 3/8" nut terminal temporarily then turn the key to the START position. If the fuse didn't blow, reconnect that wire to the 3/8" nut terminal...... then remove the large RED wire from the electric starter then again turn the key to the START position.

If the fuse still didn't blow....... reconnect the large RED wire back onto the starter and once again turn the key to the START position. If the fuse blew this time, something is very wrong with the electric starter.

If this cured your trouble shooting problem, fine. If not, and the above didn't work out for you, give us a detailed description of what you encountered at what portion of the above.