Motor doesn't want to idle

Nashville Kat

Nashville Kat

Well-Known Member
After a couple of years- not a lot of miles-
my 66 motor suddenly doesn't want to idle- either dies out or over-revs- can't find a middle ground- and suddenly I'm having to use my choke to get started, when I never had to touch it before-
66 motor with NT Speed carb and a billet intake- the only thing I've changed at is is the filter a couple months back, and from the older billet to the shorter one months before that.

any suggestions?(?)
 
No, the cable isn't binding, and it isn't running erarrtically-

I either have the idle screw set to a point it revs like crazy when I clutch, or it just dies out completely when I turn the idle screw down- there's just this line of sheer all or nothing with the idle screw -

and then the choke thing I mentioned- didn't touch it for a couple of years- now it doesn't want to start without it on, and then I have to adjust it- a pain in the adder without a cable running to it.

I tried covering the extra holes I drilled into the air cleaner a few years back, but that didn't make much difference- I've added a bit more oil to the mix, thinking it might get some kind of better afterburn- no change.
 
Sounds like you've developed an air leak somewhere. Either the at the carb-to-intake, intake-to-jug, or (god-forbid) the case gasket.

Check both intake ends first with WD-40 or something. While its near(as you can) to idle, or at least a stable rpm so you don't have to blip the throttle. Spray the WD around the intake ends, and if the rpm changes at all, there's your leak.

If the rpm doesn't change, spray around your case gasket to check it since you'll be cleaning wd-40 up anyway, just to be sure.

gl.
 
I concure. Air (vacuum) leak. As Killer suggested start with the intake/carburetor area then move on to the crankshaft seals behind the magneto rotor and the small primary gear. Your symptoms are consistent with excess air getting in somewhere.

Tom
 
I had the same problem with my motor 66 cc china girl not idling. Then I noticed it was getting leaned out somehow. I got looking and found that the screw in the crank gear in the clutch cover (right side) of the motor was out letting air in through the crank . They must not have got it tight at the factory. I put silicone on it and screwed it back in and its fine.
 
check the intake manifold to cylinder gasket.
if it's the original, they are made of a cardboard like material, and they will only last a year or 2. chances are, you have an air leak at that gasket.
 
you said you used more oil, you could be causing a lean condition there.also ck the seal used bt carb and intake could be prob.also ck air filter could be dirty.may also be getting air leak through bad gasket on head or case.spray carb choke cleaner while running to find leak. hope you find prob. good luck.peace.
 
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