GaryOak wrote: oil had leaked onto the ground near the back wheel
So many issues, where to start? Wiring issues? What kind? You say youre getting spark but wiring issues include starter relay, CDI, Stator, bystarter, etc, etc, which could be a problem. Leaking oil could be a few things also, crankcase, transmission gasket or seals or even an oil pump/line connection that leaks and makes oil travel along the case and decide to drip when it reaches the back wheel. Ive had an oil leak in the front before but doesn't drip until it travels 3ft away and drips. Need to clean the gunk off of everything and see where fresh stuff is coming from.
I am leaning towards something fuel/carb related here. Need to triple check the entire fuel path from gas tank to reeds. This includes, fuel filter, petcock, fuel lines, COMPLETELY clean carb that has been totally disassembled, vacuum port on intake, stuck/frozen reeds, etc etc.
Not questioning your ability but Ive seen it so many times where people do a "quick job" on cleaning their carb. They don't remove float or valve, They don't remove main jet or emusion tube. They don't do the "FLASHLIGHT TEST" to ensure the pilot circuit is clear. Those holes are so tiny that a grain of sand can be the difference between run and not run. Again, Im not saying youre one of these people but even someone as OCD as myself took me 2 times to get it clean.
Ive also seen people that have the spacer between the carb and intake installed upside down. That will also cause it to be restricted enough to not fire.
Thank you for the tips - don't worry I don't take any offense here. I think I did a pretty good job cleaning the carb - removed the float and its friends, removed the emulsion tube and main jet - but it can't hurt to clean it again real good (twice maybe).
You make a good point about the oil traveling across the bottom of the case before it actually drips - I will check and see if I can find where it's starting from. I'll also double check all my wiring and see if I can find anything wrong there.
Borrowed a compression tester from O'Reilly. Brought it home, screwed it onto the spark plug hole (which was a real pain), and cranked with the throttle open as you do.
First test ran 120 PSI.
Second test ran ~100 PSI
3rd: ~90 PSI
4th through 7th: ~90 PSI
--- Then I go in for dinner, thinking compression isn't the issue here ---
Come back outside -
First test: ~30 PSI
Second: ~20 PSI
3rd-8th: ~0 PSI
BUT, I had my girlfriend crank it for me with my thumb over the spark plug, and it definitely still blew my thumb off. I tried replacing the compression tester two more times but still couldn't get any readings above 0.
So I'm not sure if it's the compression tester being screwed up or if it's just very low compression and my thumb is a pansy.
Crank it with the throttle wide open to do compression testing. And try squirting some oil in into the cylinder and see if the numbers come up. Double check the hose connections on the tester. And it only takes a couple psi to blow your finger off of the spark plug hole so its not a great judge of compression.
Good point, Pat...you could've ran the cylinder dry with all that initial cranking causing blow-by. It needs juice on that bore to seal and make compression. Besides, nothing kills a motor like a dry bore!
I need to find some new haters...the ones I have are starting to like me.
Just got back from a very satisfying speed test / victory lap around the neighborhood (hit 30 mph!).
Per Pat's suggestion I put a little oil in the spark plug hole before I tested compression again. Then I figured I might as well try to start it again AND IT STARTED! Lot of smoke at first and had to keep the throttle open a bit, but as she ran more and more she got better and then I tuned the idle and air mixture screws and got her running without any throttle.
My question now is - is this short lived? What should I be looking out for now to make sure it's not a temporary fix and tomorrow it will be back to square one?
Be sure the mixture screw is set per the manual...I think its 1 1/2 turns out. Idle screw is set by ear where she purrs nicely. Wear a helmet and watch for traffic!
I need to find some new haters...the ones I have are starting to like me.
That's exciting! What likely was you issue was the carb was way off on the idle speed and mixture. Follow the manual procedure now to set the mixture and idle speed to spec now that you have it running pretty well.
If compression can go from pretty good to very poor overnight, it sounds like a piston ring was sticking in the sludge that developed over the year it didn't run. Once the oil down the plug hole partially corrected for low compression it started, and fresh mixture washed out the top end, freeing the ring for now, and maybe for good. My hypothesis is that whatever gum was causing the sticky ring got washed and cleared out. If I'm right and you keep running it frequently, it should continue reliably running indefinitely. Kudos to PTSG for coming up with the solution. Now would be a good time to re-check compression without and with added oil. Remember to apply full throttle for the check. An exhaust pipe bake and clean-out now might also be a good idea. All that oil tends to clog the pipe.
Wheelman-111
Most of my money is spent on scooterparts. The rest is just wasted.
"ISO": '03 Vespa ET4 Malossi187 74MPH
Flash 9: 2001 Elite SR Contesta 72 ZX Tran, 9:1 Gears, Stock Airbox/Carb/Pipe 58.8 MPH
Punkin: 2010 Vespa/Malossi S78, 61MPH
That's exciting! What likely was you issue was the carb was way off on the idle speed and mixture. Follow the manual procedure now to set the mixture and idle speed to spec now that you have it running pretty well.
