A 50cc Toy for the Kids – Part Two

Before reading on, if you missed part one you can read it here.

Knowing that the atv had leaked gas all over the box of my truck from when I hauled it home I told my son that he would need to start taking off all the plastic and whatnot so that we could see the guts of the machine.  We needed to have clear access to the fuel line and carburetor in order to determine where the leak originated from.  Of course the fuel tank lines would be the first items to inspect but we were able to rule those out in short order.  Without the plastic on the machine we began tracing each fuel line hoping to simply find one loose or disconnected.  No such luck.  We poured some new gas into the tank and waited for the fuel to fill the carburetor bowl.  Bingo! The fuel filled the carburetor bowl alright and then just kept flowing.  It was flowing right out through the top overflow vent and onto the ground.  It was also dripping directly off the bottom of the bowl itself.  It shouldn’t have doing either of these things.  Clearly something or somethings was/were messed up in the carburetor; so we yanked it off and stripped it down.

Identifying the Problem

What we found was nothing too earth shattering or novel.  The float was out of adjustment and wasn’t closing off the port that let the fuel into the bowl, hence the overflow condition.  We pulled it apart and readjusted the float, tested the movement and stuck it back together.  The other issue was that the carburetor bowl drain screw (at the bottom of the bowl) was so corroded that the previous owner hadn’t threaded it all the way into the body to seal off the drain port.  5 minutes with a wire brush and the threaded drain bolt saw the drain bolt fully seated and functional.  I did notice though that with the drain bolt fully seated that there was a small crack in the casting of the bowl; I backed the bolt out about a quarter turn and that seemed to tighten the crack. We also when through all the passages and ports of the carburetor with a needle to get any debris out.  Most things were pretty clean but the jet hole was completely plug by something.  A quick poke with the small pin and we could see daylight through the jet again.  Not much else to be done on the carburetor now but to throw it back together and see if it leaks? And if the machine runs?

With the gas turned back on there was a very slow drip from the bottom of the bowl but there wasn’t any fuel coming from the overflow.  We made sure we had the key on, kill switch to on, and gave the kickstarter quite a work out. Nothing. Wouldn’t start.  We kicked it nuuumerous times. Still nothing.  We watch the fuel flow from the tank, through the shutoff valve, through the filter, and into the carburetor.  There was no air in the system? Why wouldn’t the engine even pop, even a little?  We kicked it over some more, nothing.  Aaaggh! Frustrating.  “Try giving it some gas while we kick it”, I told my son. First kick and the engine sputtered.  Wide eyes and mouth hanging open on my boy. Second kick and the little engine fired to life.  My son still holding the throttle in while the cvt transmission reached its engagement point and now were proceeding out the garage doorway and into the driveway. Let off! Let off! I said.  My son, giddy with joy, is practically dancing it place now.  “Well, it runs.  Now before we put the whole thing back together, let’s just put the necessary controls on it so that you can test it out.  We don’t want to go through the whole process of completely assembling the machine only to have to strip it all down again.”  Since my son had taken almost everything off I let him work through putting the necessary items back on.  I went inside to have myself a well-earned coffee break.

The Test Ride

We pushed the machine into the back yard and proceeded to fire it back up, and it did, it ran well.  My son proceeded to ride lap upon lap around our little 1/3 acre lot.  When he finally came to a stop we realized the throttle was out of adjustment because it wouldn’t idle at all.   After a bit a tweaking and adjusting we had it idling and running laps around the yard again.  Each of the kids took turns zipping through the yard; facial expressions frequently alternating from intense focus through the corners and avoiding lawn ornaments to big smiles of pure joy as they shot through the open areas.  The little machine was well worth the $200.

We took a break for dinner and then headed back out to the garage to fully reassemble the machine; as earlier we’d left all the plastic off, and not connected everything.  It all went back on quickly as the kids were anxious to be able to ride it some more before the inevitable bed time snuck up on them.  And boy did they ride it.  I spent a fair amount of breath reminding them that they needed to ride in untouched areas of the grass so as not to wear a track throughout the yard. It’s kinda funny too because the little tires on that machine are pretty bald but even still it has enough traction to tear out the grass.

The Final Result

For a grand total of $200, and a few hours on a Saturday, we had gotten the little atv running.   Time and money well spent.