1993 Suzuki Quadrunner - Idle/Throttle Prob

[moderateatvrider]

hello everyone, got some problems with my bike that i need some help figuring out. when i start the bike itll run fine for 2-3 minutes, then it starts to rev really high(almost at max rpms) and doesnt respond right to throttle(sometimes throttle will bog it out doesnt do anything). The only way it can kind of control it (and it seems to work pretty well) is by plugging the breather hole/vent out of the bowl of the carb. When i plug that hole it stops reving really high(almost instantly) but the throttle now seems to stick(I hit the throttle and itll respond nicely but slowly idles down). Now ive cleaned out the carb around 4 times and blew it all out with an air compressor, so it should be well cleaned by now, it also now has a new diaphram installed as well.

I do know that there is a bad valve(I think its the intake valve) because its got around 155-160 psi when engine is cold but once it warms up its a little under 120psi. Also think there is a electrical issue because the head light only gets bright on the last stroke as the bike dies out(No battery installed). Not sure if either of these problems could cause this but hoping someones been there done that and knows the root of the throttle problem.

Also every time i check the spark plug its black and fluffy

Thanks in advance for ur help.

[oxidized_black]

if the plug is black, then its burning rich. i dont think the other problems are affecting the rev issue. is there fuel running out the bowl overflow where you plug it to settle it down? the throttle cable moves nice and the slide works well and isnt sticking? how are the vacuum lines on the carb? is the needle and seat working properly and is the float whole and not taking on fuel? how is the spark plug? proper heat range? hopefully a suzuki guy will jump in to give some suggestions too ...

[Tim-ANC]

Does it idle differently when you turn the handle bars?