2004 90 hp 2 stroke yamaha

[rac10860]

Idle mixture jets are set at 1 1/4 turns. It starts and runs great but seems to idle just a little rough. Carbs are clean, filters good, new plugs.

 

[ClassicAQ]

....are you soliciting for a round of applause?

 

[robert graham]

My 1999 C90 2 stroke always idles a bit rough.....just part of the 2 stroke experience, I guess.....

 

[99yam40]

Idle mixture jets are set at 1 1/4 turns. It starts and runs great but seems to idle just a little rough. Carbs are clean, filters good, new plugs.

I have no dea what the specs are, do you?

Did you do a link and sync procedure after reinstalling the carbs?
needs to be do each and every time the carbs go back on.
Plus it says to set and check timing.
just because it is set at the marks does not mean the actual timing is in spec.
Timing light helps you see

 

[rac10860]

The carbs are in sync so I guess I'll ck the timing. Thanks

 

[Sea Rider]

If everything is fine, for 2 strokes multi carb OB's perfect idle adjutment need to count with a electronic vacuum gauge, having adjusted idle screws to whatever exact in/out turns is no indication that all carbs are vacuum adjusted spot on to achieve a smooth idling.

If you don't mess with the linkages, rods that actuates carb's butterflies nor timing advance plate, don't need to do a carbs/timing advance synch every time you remove them. Just disconnect, clean and connect carbs back and voilá..

Happy Boating

 

[rac10860]

Motor shuts down after running a while, no alarms not overheating oil tank is full. No spark when it quits. Starts right up after it sits awhile. It also idles a little rough. Carbs are clean and sincranized

 

[rac10860]

Motor quits after running awhile no spark when it quits starts right up after it sits awhile carburetors are clean and synchronize linkage and timing is right on. I'm wondering if the problem could be the CDI unit that's the only thing I haven't tested yet can it be tested while it's on the motor with a multimeter to test ohms or does it have to be removed from the motor to test it

 

[99yam40]

need a DVA adapter with your regular meter to test the voltage inputs and out puts of the CDI .
service manual as all of the specs and procedures.

bad inputs = bad outputs
good inputs but bad outputs could mean Bad CDI

do a search for CDI troubleshooting

 

[Sea Rider]

Motor shuts down after running a while,

Shuts down while running or when returning throttle to idle speed after running for a while ?

Happy Boating

 

[rac10860]

Motor quits even after just idling for 20 - 30 min. No spark when quits. After sits 30 - 45 min starts back up. It is not overheating and the thermal switch checks out fine. Has new cdi unit. Pulser coil resistance is good. All 3 ignition coils secondary side tested high at 10 but that could be because they were warmer than 68 degrees. I need help I can't figure this out