New 50hp yamaha 2-stroke won't throdel past 1/4 when warmed up

Ok, I have read alot of posts and some have same problem, but I have a few things to add. Starts perfect and idles great. Will take off fine and run forever when just started and taking off. Problem is when it warms up it runs fine until I throddle down and go to take off again it acts like its fuel starved and about 1/4 throddle just when it needs gas due to getting under a load it boggs or just stalls. I can open the fuel enrichment lever and it won't bogg, but it does run rich and rough. I have cleaned the carbs twice. This motor only has about 5 hours run time on it. The electric choke seems to be working because this only happens when it warms up and I guess the needle on the choke shuts off some fuel.


any help would be great

Re: New 50hp yamaha 2-stroke won't throdel past 1/4 when warmed up

You are correct in that the Prime Start System does reduce fuel once the motor warms up.
The problem sounds like you have a carb jet or passage blockage and needs to be completely disassembled, cleaned maybe in a carb cleaner or sonic bath, and all passages blown out with compressed air before reassembling.
Make sure to do the sync and link after reinstalling the carbs and adjusting the carbs to the factory settings.