25 hp 2 stroke yamaha carb adjustment screws with no slots cut flush with carb

[e.t.]

how do you adjust carb screws on Yamaha 2 stroke 25 h.p. with 2 carbs. it was made in the last year that these 2 strokes were made I believe about 2008 or 2009? the screws are cut off flush with the carb body and have no slots. engine has only been used 5 times not even broken in yet!!!! I need to get rid of the low speed sneeze that it has. thanks e.t.

 

[midcarolina]

Those screws are supposed to be non adjustable per EPA regs......... so there is a cap covering them.

 

[robert graham]

Low speed sneeze might indicate a lean condition caused by partially plugged carb jets.....doubtful those screw adjustments are off....have carbs been removed and cleaned lately or ever?....

 

[midcarolina]

Low speed sneeze might indicate a lean condition caused by partially plugged carb jets.....doubtful those screw adjustments are off....have carbs been removed and cleaned lately or ever?....

Any late model 2 stroke wether be a boat motor or a weed wacker are set up from the factory lean in order to pass EPA regs......... Heck even most 4 strokes a setup lean from the factory..........

 

[jerryjerry05]

Are they caps or plugs?
Can they be removed?
A lot of carbs aren't adjustable and cleaning is the only thing that can be done.

 

[midcarolina]

Below is a link to a video showing how to remove the plugs.........they are showing a motorcycle carb, but it gives you general how to.

 

[boscoe99]

As implied, I think that you are looking at the EPA caps that cover up the idle mixture screw. You need to remove that part to gain access to the idle mixture screw.

While counting the number of turns that it takes, turn the screw inwards until it lightly seats. Write down the number of turns. Back the screw out the same number of turns that you counted when screwing it inward. Then, back the screw out maybe half a turn to see if the sneeze disappears. Or, maybe try half a turn inwards from the original position. Whatever it takes to improve the idle quality.

The idle mixture jet is a number 60 size. You might want to get maybe a number 62 or 64 and give it a try if you can't get the motor to stop lean sneezing.

 

[Perk_zk]

Any ideas on an adjusment to get the motor to a fast idle? Mine idles good then with a little bit of throttle u hear the carbs open but gain no speed until about 1/4 throttle then it tries to jump on plane. Not thryin to hijack ur thread but this is the closest thing ive found that relates to my issue. Wot awsome. Idle awsome. Has bit of trouble after you go wot to off at restart. Thanks