Hello to all,
I know carb issues have been addressed a lot here and I have looked at a lot of posts. But I am going to ask a different question after you see this brief description.

Recent acquistion from brother and it has not been sitting to gum up carb.
Idles good. Pops, farts, stumbles from exhaust and carb intake with any gas applied. Replaced the plug, blew out the carb with compressed air and did a quick rebuild with new jets (all stock sizes), gaskets. The needle clip was set at position 2 with the A/F mix screw 3 turns. Not having the manual to know how many turns out the screw should be, I left the A/F screw alone but set the clip at position 1 on needle (rich). It ran best there but not fantastic.

But Wait!! The problem is intermittent! Ran as described the other day. Added sea foam to gas yesterday and it ran great except for 3/4 - full. idled and accelerated pretty well. Tried today and it was right back to crappy running. Same symptoms.

I will take the carb apart again for a sea foam soak and to reset the clip to position 3 and screw out at 1.5 turns to assess. Love some advise about that,
but I wonder about the battery. Does the battery contribute the power for full spark at higher RPMs? I can tinker but I'm not a small engine guy. I am use to Landcrusiers...not ATV's.

Love some help. Thanks to JustRandy and Nedflanders for previous input.

 

Of course you put a new spark plug in it... And the ignition wire is checked or replaced? Takes more spark to light under operating cylinder pressures than at idle.

Is your gas any good? Not stale?