1990s Yamaha 70 bogging and dieing at half throttle! Help

[Haydondo]

I have a 1990s Yamaha 70 2-stroke (70BETO)
its starts after a few turns of the key and idles excellently and revs great but when I put it in gear
it revs at quarter throttle fine the when you get to about 1/3 throttle it Boggs and dies carbs a clean and filters to this accoured after I adjusted the pilot screw on all 3 carbs even after factory spec please help!!
Thanks

 

[rejesterd]

The pilot screw shouldn't matter at 1/3+ throttle, so something else is up. Maybe an air leak or just low compression. I would check compression in all cylinders and confirm it's ok before you sink anymore money into it.

 

[Haydondo]

Cheers mate I will test compression and report back

 

[robert graham]

Ware you sure the internals/jets of carbs are really clean?...

 

[Haydondo]

Hi yes carbs are clean and no vacume leaks found and compression test went fine I’m really confused I’ve also replaced spark plugs and wires, fuel lines and filters also oil level sensor working normally. Any more ideas? Thanks

 

[Jack12]

Sounds like you somehow knock your time and sync out of line