[XplicitRacing6]

I know this is a Honda Forum but I figured you guys still can help.
My 1986 Yamaha 220 seems to have a problem. Everytime I start it up (Motor cold) it idles extremely high. Like close to redline.
After I let it sit and warm up it idles fine.
After riding it for around 15 minutes and it gets hot; it doesn't want to idle. I turn the idle screw, idles fine. Ride around for 15 minutes- then it goes back to not idling. I hope you guys can help cause I'm stumped. I just recently got an oem carb and it runs way better, but it wasn't doing this before.

 

[mrbb]

I'm thinking its NOT jetted right
and or carb is NOT clean
could be a fuel issue, poor flowing lines, causing things to run like it is
MY atv ALWAYS need a idle adjustment from, warm weather to cold, but NO issue's with it changing after warming up, or very slight if any difference

have you tried draining the fuel out and going with new fuel?
is the air filter good and clean and allowing good air flow?

 

[SamUK]

Check the choke valve. I’d also be tempted to look at the rubber boot (and it’s seals) between carb and head.

 

[alloutdoors]

My 1986 Yamaha 220 seems to have a problem.

Like Mrbb, I think you are fighting a carb issue (jets, cleaning, etc., and in the worst case perhaps it needs replaced completely) on this 32 year old machine.

Curious you running ethanol enriched fuel and if so, that may be causing havoc on the fuel lines, carb, etc., so a fresh cleaning of the tank, new lines, cab cleaned/adjusted with non-ethanol fuel may do the trick as well...

 

[JohnnySolo]

I'm thinking its NOT jetted right
and or carb is NOT clean
could be a fuel issue, poor flowing lines, causing things to run like it is
MY atv ALWAYS need a idle adjustment from, warm weather to cold, but NO issue's with it changing after warming up, or very slight if any difference
have you tried draining the fuel out and going with new fuel?
is the air filter good and clean and allowing good air flow?

Check the choke valve. I’d also be tempted to look at the rubber boot (and it’s seals) between carb and head.

My 1986 Yamaha 220 seems to have a problem.

Like Mrbb, I think you are fighting a carb issue (jets, cleaning, etc., and in the worst case perhaps it needs replaced completely) on this 32 year old machine.

Curious you running ethanol enriched fuel and if so, that may be causing havoc on the fuel lines, carb, etc., so a fresh cleaning of the tank, new lines, cab cleaned/adjusted with non-ethanol fuel may do the trick as well...

I agree with these guys, be sure fuel is good and flowing nicely, check air vent for tears or being dirty, be sure air intake tube isn't clogged or covered (should be attached to air box) and you may have to take apart carb and clean it, sounds like coule be a dirty carb or jet problem. If all these things are good and it still is doing it then that's a Yamaha for ya. Good luck

 

[Goober]

Your quad getting very hot? If fan coming on like it should?

 

[XplicitRacing6]

I'm thinking its NOT jetted right
and or carb is NOT clean
could be a fuel issue, poor flowing lines, causing things to run like it is
MY atv ALWAYS need a idle adjustment from, warm weather to cold, but NO issue's with it changing after warming up, or very slight if any difference

have you tried draining the fuel out and going with new fuel?
is the air filter good and clean and allowing good air flow?

I've run multiple tanks through. I only run ethanol free fuel. I haven't check the air filter but I just put a new one in 2 months ago. I'll check it though. thanks

 

[XplicitRacing6]

Check the choke valve. I’d also be tempted to look at the rubber boot (and it’s seals) between carb and head.

Thank you I will check

 

[XplicitRacing6]

My 1986 Yamaha 220 seems to have a problem.

Like Mrbb, I think you are fighting a carb issue (jets, cleaning, etc., and in the worst case perhaps it needs replaced completely) on this 32 year old machine.

Curious you running ethanol enriched fuel and if so, that may be causing havoc on the fuel lines, carb, etc., so a fresh cleaning of the tank, new lines, cab cleaned/adjusted with non-ethanol fuel may do the trick as well...

I only run 91 octane ethanol free fuel. It's a brand new oem carb I just put it in not even 4 months ago. I did have to replace some of the fuel lines so I don't think it's that either.

 

[XplicitRacing6]

I'm thinking its NOT jetted right
and or carb is NOT clean
could be a fuel issue, poor flowing lines, causing things to run like it is
MY atv ALWAYS need a idle adjustment from, warm weather to cold, but NO issue's with it changing after warming up, or very slight if any difference
have you tried draining the fuel out and going with new fuel?
is the air filter good and clean and allowing good air flow?

Check the choke valve. I’d also be tempted to look at the rubber boot (and it’s seals) between carb and head.

My 1986 Yamaha 220 seems to have a problem.

Like Mrbb, I think you are fighting a carb issue (jets, cleaning, etc., and in the worst case perhaps it needs replaced completely) on this 32 year old machine.

Curious you running ethanol enriched fuel and if so, that may be causing havoc on the fuel lines, carb, etc., so a fresh cleaning of the tank, new lines, cab cleaned/adjusted with non-ethanol fuel may do the trick as well...

I agree with these guys, be sure fuel is good and flowing nicely, check air vent for tears or being dirty, be sure air intake tube isn't clogged or covered (should be attached to air box) and you may have to take apart carb and clean it, sounds like coule be a dirty carb or jet problem. If all these things are good and it still is doing it then that's a Yamaha for ya. Good luck

Haha.... I mean it was 200 bucks and it had 5 hours on it. It is in immaculate condition. Thank you i will check on that stuff

 

[XplicitRacing6]

Your quad getting very hot? If fan coming on like it should?

It does get hot, but nothing crazy. It does not have a fan.

 

[SamUK]

Getting hot would suggest running lean (more air than fuel), my guess is you have an air leak on the pipe from head to carb or a partially blocked carb.

If the inlet hose/pipe is split or leaking it will cause iratic idle and will change as the engine warms up. Not all of the time, but most.

When you dig into the carb pay close attention to the emulsion tube, this is usually a brass tube with cross drilled holes. Those cross drilled holes need to be 100% clear.

The trick to cleaning a carb is, clean, clean and clean again, if your unsure your attempts aren’t good enough then keep on cleaning.
I always rebuild mine on a piece of white paper or plastic, makes all the specs of dirt more noticeable.

 

[XplicitRacing6]

Getting hot would suggest running lean (more air than fuel), my guess is you have an air leak on the pipe from head to carb or a partially blocked carb.

If the inlet hose/pipe is split or leaking it will cause iratic idle and will change as the engine warms up. Not all of the time, but most.

When you dig into the carb pay close attention to the emulsion tube, this is usually a brass tube with cross drilled holes. Those cross drilled holes need to be 100% clear.

The trick to cleaning a carb is, clean, clean and clean again, if your unsure your attempts aren’t good enough then keep on cleaning.
I always rebuild mine on a piece of white paper or plastic, makes all the specs of dirt more noticeable.

Thank you for the help. I guess i'll tear down the carb and see what junk I can get out of it

 

[redtherocket]

I'm with Sam on this one...

Shes leaning out...