2003 150hp Yamaha 2 stroke no vacuum at 2 carburetors

Tdawley

Cadet
Joined
Oct 22, 2017
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good morning, I have a 2003 Yamaha 2 stroke o/b. The issue I'm having is that I am getting vacuum from only one carb. I am getting very little to no vacuum from the other two. Compression is at 125 for all 6 cylinders and I have great spark. While at idle, if I pull the spark to off the cylinders the engine will stall. However, if the engine is idling and I pulled the spark book off of the other while at idle, if I pull the sparks off the good cylinders the engine will stall. However, if the engine is idling and I pull the spark book off of the other son cylinders there is absolutely no change in sound or performance. Could this be the reed valves? Or do I have a vacuum leak somewhere else that's affecting those two other carbs and cylinders. The middle card and two cylinders are the only ones that are really doing any work.

Model 150TXRB

I would appreciate any input, criticism, or any help to get this running on all six cylinders!
 
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