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Discussion Starter · #1 ·
I have a 97 300ex that I bought as a project. After changing the gas, oil, and cleaning the carb I started it for the first time the other day. It started up easily but as it warms up it idles higher and higher, turning the idle screw only has a minimal effect. The idle screw itself is turning and is not stripped. I'm not sure what the problem is, maybe it is getting way too much air. It is missing the metal inner core in the air filter, but i think the difference in airflow is probably too minimal to cause the high revved idle issue. Anyone have any ideas? I'm not sure where to start. Also the choke does seem to work....
 

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Discussion Starter · #4 ·
I would start with checking around the carb boot to make sure there is no air leak between the carb and motor.


Also change the spark plug if you didn't already.
exactly where i started, no leaks at the air boot and I put a new NGK plug in it, gapped to specs.
 

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Discussion Starter · #6 ·
The cable is not binding anywhere, I haven't messed with the air/fuel mixture yet. The idol screw lets it idol down a little bit but it is not as responsive as it should be. I noticed today that my crankcase vent box is missing, there is just a hose connected to the head that opens in 2 places. I tried plugging it up but it didn't change things much, is it okay for those hoses to be left open?
 

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Did you put the cable back on the carb throttle cam correctly? If you cleaned the carb exactly how did you clean it? I think you have some trash in the idle circuit somewhere??
 

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I have a 97 300ex that I bought as a project. After changing the gas, oil, and cleaning the carb I started it for the first time the other day. It started up easily but as it warms up it idles higher and higher, turning the idle screw only has a minimal effect. The idle screw itself is turning and is not stripped. I'm not sure what the problem is, maybe it is getting way too much air. It is missing the metal inner core in the air filter, but i think the difference in airflow is probably too minimal to cause the high revved idle issue. Anyone have any ideas? I'm not sure where to start. Also the choke does seem to work....
you have something plugged up inside the carb rebuild it completely soak it over night in a can with parts cleaner then go after it with a piece of welding wire to get at the holes.
 
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