1987 50 hp mercury, no spark

[nitro2000dc150]

New project, well maintained boat with 50 hp mercury ser. #A717583. sat for 5 years. Did fuel pump, water pump, lower unit oil, poured marvels mystery in all openings let soak then drain. Starter spins great but no spark. Have Clymer manual but it is vague on ignition trouble shooting. Any advice and short cuts would greatly appreciated. Thanks in advance

 

[Faztbullet]

Download the CDI troubleshoot manual and test the stator outputs....

 

[Barnacle_Bill]

Also make sure you are testing with the motor down in run position. If you are doing that try disconnecting the black/yellow wire on the switch box and recheck.

 

[nitro2000dc150]

Follow up. Got spark (replaced switch box). Ran ok at first then progressively got worse. Got it to stay running running at high idle (1000 rpm). Pulling #2 wire no change in speed. Not good considering it has spark. Compression test was ok prior to running. Walked away got a beer, afraid to recheck compression

 

[nitro2000dc150]

Compression within 5 lbs. engine is good. Look at all possible causes. I guess

 

[nitro2000dc150]

OK, runs but pulling # 2 or 3 or both plug wire, no change. put 3 wire on 2 plug dies immediately. Pull 1 wire dies immediately .3cyl. 2 carbs.Total cleaning of carbs new needle valves and float height checked. Top carb idle adjust ok. Bottom carb idle adjust not as good. gonna switch carbs and re check. Any advice greatly appreciated and thanks in advance.