1999 200 hp Yamaha Carb Question

[windknotnc]

I recently put a 1999 200 Yamaha SWII Model #SX200TXRX on my boat and had the carbs cleaned at a local shop to solve a rough idle problem. During this I was told that the middle carb on the engine was not the correct carb. When you look straight at the carbs the throats of the top and bottom carbs appear to be the size of a 1/2 dollar. The middle carb throat is the size of a quarter. Is this correct? I have read that the prime start system enriches the middle carb so I was wondering if that had anything to do with it. Regardless, the engine is still not idling well and sometimes cuts off and sneezes a little then cuts off. It is also rather difficult to start requiring several 5+ second key turns with the key pushed in before it will hit. Any way, if there is any advice or answers to the carb questions it would be greatly appreciated.

 

[windknotnc]

Re: 1999 200 hp Yamaha Carb Question

Added Model # The first picture is all three carbs. Notice in picture 3 that the throats on the middle carb is smaller than the top and bottom. The numbers stamped on the top and bottom are 64ESO and the middle is 6G405.

 

[Captn Dave]

Re: 1999 200 hp Yamaha Carb Question

No, that isn't the right carb. I have a 1997 200 which is basically the same engine.
Try finding a used carb from a place that rebuilds engines.
By the way, is that the right model number? According to some online parts diagrams, the SX signifies it's a fuel injected motor.

 

[mobilemike]

Re: 1999 200 hp Yamaha Carb Question

I'm with captndave on this one. I wonder if the power head has been changed. Check to see if the black and white serial number sticker is still on the block,and that it matches the one on the bracket. SX is the designation for an ox66 efi.In any case the sneeze and hard starting indicate a lean condition.I built some carbs the other day that had mismatched main and idle air bleed jets. Ran like a pig until i sorted it out. I'd get the right carb and go from there.