My 66cc engine with nt carb has never ran how it should. Its super rich and the needle is as low as it will go. It 4 strokes for about 30 seconds on Full throttle then it starts running better and picks up alot of power anf even pulled me to 39 mph at wot but after you let off the gas it 4 strokes a little and will only go like 25 mph. I lowered the float twice which helped tremendously and ride without the air filter with a clean carb. I also had a head leak which i fixed and sealed and now it seems like it runs even a little worse and now it wont lean out at wot at all so im thinking im gonna have to rejet smaller but any advice?
Running extremely rich , no Air leaks
- Thread starter Rmountcastle001
- Start date
About 70 now and yeah i think i just need to rejet.... i can only get it running so good with the float adjusting ... also it has very idled...
Plugs black and like i said it leans out a little bit after 20 seconds at full throttle and goes faster and im using 16:1 which is a lot of oil i know but even so the engine should want to run leaner with that vs. 24:1 so thats how rivh its running. Plus the needle is on the lowest setting to let the least amount of oxygen in
Drop your oil ratio to at least 24:1 and give the engine some time before trying to get top performance from it. 200 to 300 miles and then start playing with jets and other things. 70 miles isn't enough to get a clear view of what the engine wants or needs, except a lot less oil.
Tom
Tom
But why is it that it wont idle then? Or run right? Because most people put it together ouy of the box and it idles immediately and stuff
I have a similar issue althought not as extreme. When I'm throttling up it has about ten seconds of really nice humming rpms and at close to "top speed" it starts sounding really throaty and stops going much faster.
It's kind of weird. It sounds almost like an actual dirt bike at a point then it gets all throaty at top rpm.
Any ideas? Maybe I should try a run with the carb-filter. off and see what happens.
It's kind of weird. It sounds almost like an actual dirt bike at a point then it gets all throaty at top rpm.
Any ideas? Maybe I should try a run with the carb-filter. off and see what happens.
if the idle screw is turned all the way in and it still won't idle, then I suspect you have the needle clip set wrong - the clip should be at the top to leave as much of the needle as possible hanging down in the carb
It will NEVER run right with 16:1 in it.
Listen to 2door and switch to 24:1 or even 40:1
I use 40:1 in all my twosmokes.
In post #8 you said this:
"Plus the needle is on the lowest setting to let the least amount of oxygen in"
If you have the 'C' clip in the lowest notch that is allowing more fuel to flow from just off idle up to about 3/4 throttle. Move the clip to the second from the top.
Tom
"Plus the needle is on the lowest setting to let the least amount of oxygen in"
If you have the 'C' clip in the lowest notch that is allowing more fuel to flow from just off idle up to about 3/4 throttle. Move the clip to the second from the top.
Tom
Here is what I would do if I couldnt afford to buy a real carburetor:
Buy a micro drill bit set and use it to drill the main jet hole after soldering it shut (by using flame and solder). At WOT the needle position is unimportant, just the main jet size matters. Experiment with different hole sizes. I like mine just one size richer than what gives me the best top speed. Then position the needle for best starting and idling. It should be rich enough to start a cold engine on a warm/hot day (above 80). Too rich causes it to sputter going downhill with partial throttle. Then if it is too rich for mid throttle acceleration you can heat the needle and put solder onto it to lean out the mid range. Or, you can set the needle height for best acceleration and then add solder to the lower part of the needle for best idling. In my experience manipulating the needle width with solder is the only way to get all three ranges (low, mid, high) right.
Or just put that sorry excuse for a carburetor in the trash where it belongs and get a good carburetor that is fully adjustable like the Walbro from JNMotors.
Buy a micro drill bit set and use it to drill the main jet hole after soldering it shut (by using flame and solder). At WOT the needle position is unimportant, just the main jet size matters. Experiment with different hole sizes. I like mine just one size richer than what gives me the best top speed. Then position the needle for best starting and idling. It should be rich enough to start a cold engine on a warm/hot day (above 80). Too rich causes it to sputter going downhill with partial throttle. Then if it is too rich for mid throttle acceleration you can heat the needle and put solder onto it to lean out the mid range. Or, you can set the needle height for best acceleration and then add solder to the lower part of the needle for best idling. In my experience manipulating the needle width with solder is the only way to get all three ranges (low, mid, high) right.
Or just put that sorry excuse for a carburetor in the trash where it belongs and get a good carburetor that is fully adjustable like the Walbro from JNMotors.
Lol i know how the neefle works and i have it set the best its gonna be (the clip is on top notch, therefor letting the needle go lower and less oxygen enter)
The motors need time to loosen up and get lubricated and worn in and rings need to set. The 16:1 ratio is not helping it run well, too much oil. Do you have air leaks? is your head torqued properly? Did you throw some light weight oil down your throttle and clutch cable houseings? Are your throttle/clutch cables routed with bends that are (too) sharp, or tied down too tight causing drag? Is your choke operating properly? These things effect idle....
Idling perfect right outta the box? You must be a comedian? LOL
Needle position ('C' clip setting) has nothing to do with air (oxygen). It only controls the amount of fuel delivered to the engine. The clip position determins how high the tapered needle is lifted out of the main jet.
Tom
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uh, the needle goes down into the FUEL JET and limits/controls the amount of FUEL that comes through the jet, it has nothing to do with how much air your motor is getting....
