Yamaha 70 hp 2 stroke running horribly in mid-range

[mikedavidson]

I HAVE A 2006 YAMAHA 70 hp 2 stroke that is giving me fits. ill just post the video and maybe you can tell me where to start. it idles good, and does ok at WOT but in between its thrashing. I'm not sure where to start. Well, actually I have started- with new plugs, coils, ECU, fuel pump, carb gaskets. compression great. HELP

Here is a 1 min video https://youtu.be/AE5rRCHDvXI

[robert graham]

Have the carbs ever been cleaned? …..

[mikedavidson]

Yes I took them off removed bowls and cleaned

[ausnoelm]

You need to clean more than the bowls! Yamaha carbs are very difficult to clean, you can't just spray them or wash them, remove them and clean every passage, including the ones in the carb body as wel, as the jets.

[99yam40]

and follow the link and sync procedure in service manual when you put the carbs back on, it includes verifying the timing is in spec too

[mikedavidson]

ok, ill take them back off and go through them - thanks- I'll let you know.

[mikedavidson]

Ok WOW- I started with the middle carb cyl 2. I took it completely apart and there are LOTS of passages including what Yamaha calls an enriching fuel pump on the side underneath the ELECTROTHERMAL VALVE I'll be ordering carb kits locally. I will completely rebuild all three. I found a crease in the diaphragm on the enriching fuel pump I will be replacing it. ill let you guys know with details

HERE IS LINK TO PIC SHOWING THE SMALL INFRACTION IN THE EFP
https://parkwayautomotive-my.sharepo...MRbTQ?e=vpEmFr