Misfiring Suzuki outboard DF 70 4 strokes

[philoudent]

Hello everybody, I'm new on this forum and i hope you can help me with my engine problem .

I took a video, the sound isn't perfect but you can see what happens

Misfiring starts at 5 minutes running, no matter the engine rpm. they stop when i slow down at 3000 rpm. There is none alarm

The motor is a second hand, built in 2008.

Trying to fix it we :
- did computer diagnosis ( no failure)
-changed all filters (oil, air, water separator)
- put additives in fuel like water remover and injectors cleaner
- cleaned fuel injection rail and injectors manually
- controlled high pressure fuel filter

Despite it none amelioration
Does anyone has an idea ? We're trying to think to everything, temperature, pressure, electricity, defective part ... Our local mechanic is thinking about a bad contact in the vapor separator tank. We're waiting for a new cable ....

Thanks for your help

 

[gordmac]

Have you tried a set of plugs? Coil breaking down? Plug leads?

 

[Mr Googler]

As above, start with the simple stuff. HT leads and spark plugs. You could also slightly pull the ht lead off the plugs one at a time. The one that doesn't effect the running is the problem one. Careful though, you don't want stray sparks really

 

[Keith-i]

Partial fuel blockage?

I know the ECU limits them to 3k rpm when out of gear so perhaps something wrong with a sensor somewhere telling it that it is in gear.