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I searched and searched but couldn’t find exactly what I was looking for so figured I would join the group and try to see if anyone could help!
It had been sitting for ever so I pulled the carburetor and tank and cleaned both and jets of course, replaced in tank fuel filter and then reassembled.
since reinstalling it started right up and ran and idled so I shut it off and now when I go to start it, it idles almost perfect on choke and then the RPM’s skryrocket when I turn the choke off.
I pulled the air box lid and filter and stuck my hand over intake cover and it brought the idle down so I imagine it’s an air/fuel ratio problem but where is that adjustment? I see the idle mixture screw but feel blind since I can’t figure out where the adjustment is for air/fuel... Sorry for the novel lol
Any help and guidance is much appreciated!
Thanks
 

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I imagine it’s an air/fuel ratio problem but where is that adjustment? I see the idle mixture screw but feel blind since I can’t figure out where the adjustment is for air/fuel... Sorry for the novel lol
Any help and guidance is much appreciated!
Thanks
Idle mixture screw and air/fuel adjustment is the same thing - they are the only two adjustments that can be made from the outside of the carb.

The fuel mixture screw is #5 - the idle speed screw is #7 - let me know if this helps
4095
 

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Idle mixture screw and air/fuel adjustment is the same thing - they are the only two adjustments that can be made from the outside of the carb.

The fuel mixture screw is #5 - the idle speed screw is #7 - let me know if this helps
View attachment 4095
I don’t feel like I see “5”/idle mixture screw. You don’t have a picture of an actual trx carb do you sir?
Thank you!
 

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No, I don't have a pic AND I haven't seen a TRX 90 for a few years - here's a pic from the service manual with highlights - it's possible the fuel screw is capped to make it tamper proof (government watching out for our health) - if it is capped, the cap will have to be removed - you drill a small hole in the cap - the tricky part is you don't want to hit the screw below the cap with the drill bit - run a small wood screw into the hole you drilled and use pliers or vice grips to pull on the screw and remove cap - you can then turn the screw in, counting turns, until it seats lightly so it can be set back to the same position simplifying resetting after cleaning.
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No, I don't have a pic AND I haven't seen a TRX 90 for a few years - here's a pic from the service manual with highlights - it's possible the fuel screw is capped to make it tamper proof (government watching out for our health) - if it is capped, the cap will have to be removed - you drill a small hole in the cap - the tricky part is you don't want to hit the screw below the cap with the drill bit - run a small wood screw into the hole you drilled and use pliers or vice grips to pull on the screw and remove cap - you can then turn the screw in, counting turns, until it seats lightly so it can be set back to the same position simplifying resetting after cleaning.
View attachment 4096
That’s the ticket! I saw that cap and wasn’t sure if it was there or not! Do you think to pull the carb and clean it again or go straight to adjusting fuel ratio?
Thank you so much
 

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I would pull the carb to work on removing the cap - once removed, turn the screw in till LIGHTLY seated, counting the turns then remove the screw and reclean the carb.

Note in the part breakdown previously posted; there is depicted 2 fuel screws - #5 and #23 - #23 has a cap and 2 o-rings while #5 is just screw, spring, washer and o-ring - you will need to fashion a small pick to extract the washer and o-ring from the bottom of the fuel screw hole - assemble the screw (put the spring on first, then the washer and last the o-ring. I mention this as most people don't know the parts are there and either lose them or put them together wrong.
 

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I would pull the carb to work on removing the cap - once removed, turn the screw in till LIGHTLY seated, counting the turns then remove the screw and reclean the carb.

Note in the part breakdown previously posted; there is depicted 2 fuel screws - #5 and #23 - #23 has a cap and 2 o-rings while #5 is just screw, spring, washer and o-ring - you will need to fashion a small pick to extract the washer and o-ring from the bottom of the fuel screw hole - assemble the screw (put the spring on first, then the washer and last the o-ring. I mention this as most people don't know the parts are there and either lose them or put them together wrong.
Thank you sooooo much for all the help! Really appreciate it!
Thanks
 

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That's why I'm here, but it's not 24/7 - there are several hours each day that I have to work at a real job and that job is 11+ hours a day and 7 days a week - only time off for doctors, birthdays and some holidays - I worked last Christmas day, New Years day and am working through Illinois's COVID-19 quarantine.
 
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