Re: what is this part for pic included
Yes. Especially if something sucked into one of the carbs and is blocking a few open. However it would be more likely to be 1&2 or 3&4 or 2&4.
I doubt your problem would be in the carbs because that would affect 1&2 or 3&4.
I'm thinking that you have a spark problem. It probably isn't the stator because two cylinders are apparently getting spark. It could be two coils, but chances of two coils failing at the same time are slim. That leaves the trigger and switchbox.
On the water jacket cover by the sparkplugs, the firing order will be embossed. The ignition triggers operate in pairs. The first and third cylinders in the firing order are paired, and the second and fourth cylinders in the firing order are paired. If 1&4 are one of those pairs, you may have a broken wire in the trigger.
The switchbox can fail anything from one to all four cylinders.
But let's not start replacing parts without some diagnosing. If you have access to a compression gauge, it would be helpful to know if the cylinders are healthy. It would also be good to check for spark. You can remove the sparkplugs and lay them on the block and watch for spark. You can also use a timing light. If the light flashes, the sparkplug is sparking. Just check each wire in turn.
Remove the sparkplugs and tell me how each cylinder's plug is burning by the deposits left behind. Dark brown and slightly damp looking is ideal. Clean means it's not getting spark, or maybe no gas or way too much gas. Black and shiney means the plug is probably fouled. Gray would mean a bad internal problem with the cylinders.
