The Elusive Go Kart Engine - Smoking, Choking and Backfiring - What is That All About?

One of the most valuable lessons to be learned whenfor the elusive problem.
playing with go karts is engine repair. Also, like any bigAnd after I tore it apart I had to laugh, and be
problem to solve, some of the engine problems can beeducated. The points on the engine had a spring that
very elusive and frustrating. I had this engine that justkeeps the points coming back into position. Trouble
would not run right. It would run, but not fast, and it waswas, the spring was on sloppy, and allowed the points
very frustrating.to literally float as the rpms increased. So what
What would occur is that the engine would start andoccurred was the engine was literally losing spark at
run just fine, but when the throttle was opened up thethe higher rpms. The floating points acted like a
engine would just back fire through the carburetor, outgovernor. Old "his and pop" engines actually use this
the exhaust, blow black smoke and just would not getmethod for slowing their engines down. Instead of
past really anything but idle. You can imagine myplaying with the throttle, they play with the ignition to
frustration. I have this elaborate strait tube intakeslow the engine down.
(which really is a high rise manifold) and this oversizeOnce the engine was reassembled the engine ran full
carburetor mounted to this 4 horsepower Briggs.throttle no problem. Understanding the reasons why
I had that engine torn down probably twice. Removedengines behave the way they do is very important in
the head, checked the valve clearances, tore apart thediagnosing the problem. One of the elusive things about
carburetor, added more sealant to the intake runnerthis problem though is the assumption that the points
and the carburetor interface...all to NO avail. The engineare fine, that the spark is consistent. The trouble
still ran like junk. Having just exhausted all remedies, Ishooting motto is question everything and exhaust it at
took off the engine and tore it apart completely lookingthe least cost.