Just bought 1997 Fountain with (2) HP500's. The starboard engine will turn over, but never fire. Guy just replaced the coil and pickup module in distributor and it fired up and ran fine. Took it out today and it just kept turning over and would not crank. I put the firing wire (from dist. to coil) off of port to starboard and it fired up and ran fine. After running the boat a bit we stopped and when I tried to crank starboard it wouldn't fire AGAIN!! What could be the problem??? Also, what should oil temp be in these motors??

Check all your grounds.

Check the main elec round connector and see if there is corrision, loose pin's,etc

Check the kill switch. Unplug it and plug it back in .

All good advice. I'll bet it is one of those 2 items mentioned. Did you check it for spark when it wouldn't start. If it does not have any spark when you are cranking it over, then check all of the connections on the distributor, coil, ignition module, etc. If it does have spark, then your problem is going to be fuel/carb. related. I would bet that it does not have spark when it will not start. Good luck.
Eddie

Thanks for the replies..I need a wiring diagram for the hp500, for the coil wiring and distributor ignition control module. All connections seem fine at module and at coil, where are the other ends so they can be checked or reference me to a diagram?

check the tether,also check the ignition switch for loose wire..

There are ignition troubleshooting guides in merc manuals. They are simple and make it easy to figure out whats wrong. They have been posted on OSO before, but I don't where they are.