I have a 1986 Yamaha 3 cylinder 70 ETHJ that sometimes runs fine but then the top cylinder stops working. I have cleaned the carbs, switched the ingition coil with another one that is working, did a compression test and all cylinders a fine. I did a spark test and I get no spark on top cylinder when problem is present and spark is there of course when it is running ok. It has new plugs and when it has the problem and i remove the top plug it is wet with gas. Any idears what to do next?
