Wet & Oily spark plug and intake manifold  By  bigmac (Read 4,640 times)

Perhaps your fuel flow is not enough or consistent if it dies shortly. Maybe you got a bad tank of gas and clogged your fuel filter. Also, make sure your new fuel filter is the correct direction if directional. There might be an arrow on the plastic housing of the fuel filter.

As, long as there is spark, your old and new carb didn't get dirt in it, and you have good air flow, then look at fuel. You can also look for vacuum leaks by spraying carb cleaner around the areas where there could be a leak. The only thing is the engine has to be running for that to work.

Good luck.

I took out the cylinder head and removed the valves for a careful cleaning and inspection. Taking them out was easy thanks to this video:


But putting them back in was a bit tricky, but possible thanks to this video:


Other than being very dirty with carbon deposits, the valves looked fine so I put the engine back together without replacing them. After that, the engine would not start. I even sprayed starter fluid right into the spark plug hole without any luck.

Frustrated and clueless as to why it wouldn't start, I began pushing down the kick start lever over and over in frustration when suddenly I heard a small sputter. I kept going and heard more sputters. The engine started to turn over a few times with each kick. Eventually, it started to run and the spark plug and intake manifold were dry afterwards.

So I guess I could have fixed it by simply cleaning the valves and the valve seats. At least I learned some new things. I never took apart an engine that much before.

Even now I don't know if it was actually oil. The wet, oily residue smelt like gas and evaporated quickly, so I suspected it was gas mixed with carbon deposits giving it a blackish color. I wanted to inspect the carb, but other than the float bowl screws, all the other screws were stripped. The breather pipe had dry rotted and fallen off, the float bowl was leaking badly, and the air/fuel adjustment screw was capped.

When I saw how cheap a complete carb that's ready to go was, I decided it would be worth it compared to working on the old one.

Yeah, it runs fine when it's not at idle. Unfortunately, I haven't had anytime to ride it since I last worked on it.

Both the intake and exhaust valves are currently set to .003. I had the exhaust valve set to .004 before, but it always seemed pretty loud, even after being fully warmed up.

Yeah, the tapping/pinging was much louder than it was before. The scooter's original valve clearance was .002 for both valves and there weren't any issues for the first 2,000 miles.

After those 2,000 miles, I started to experience stalling after the engine had warmed up. That's when I first adjusted the valves. I checked them before adjusting and found both to be .002. The stalling turned out to be due to the carb flooding though. So the valves have been set tighter than they are now without any issues.