Idle Agitations

[Bailey 0]

Ok .... 3012, starts quickly and idles pretty at part choke. Started at factory settings and can't get a good idle without the choke, unless the main needle is waaaay out. Like 4 full turns vs. the 1 1/2 the manual suggests. Also tends to want to sputter on the way to WOT. Once you get there it settles down, but makes me think it'll sputter under a load. Any ideas?

[427435 0]

I don't know about the particular engine in a 3012, but every small air-cooled engine I've worked on also has an idle mixture needle. It sounds like that needs to be opened. One thing I do when a carb is acting up is to gently turn the needle all the way in (in case something has blocked the hole) and then turn it out 1 and 1/2 turns (either the main or idle needle). It will usually run with that and you can adjust for optimum from there.

[goatfarmer 817]

Vaccuum leak, maybe a loose intake manifold bolt, or carb mounting bolt.

[UCD 14]

Vacuum leak = warn throttle plate shaft, bad carb base gasket, bad intake manifold gasket. With engine running at idle spray a water mist with a Windex bottle around the throttle plate shaft, base gasket, intake gaskets, one at a time. When the engine smooths out that is where your vacuum leak is.

[HubbardRA 19]

One other thing to look at. If the engine hesitates when you open the throttle, you should open the main jet just a little to stop the hesitation, then readjust the idle. If the main jet is set too lean it can affect the idle mixture.