Vespa 150 wont start

[russell]

 
Having changed the speedo cable on my vespa px and then kickstarted the same to test the speedo I took the scooter up the road and back when slipping the gears into neutral the scoot cut out. Since then, 2 days ago I can't get the scooter to start. I have checked the carb and have fuel running to the same, the float and needle are great, put a new spark plug in and have a good spark when tested the same against the body also have good compression and now a headache. The vespa has kick and electric start but neither will get the scooter going. Also tried bump starting it but to no avail. Any help would be appreciated.

[phattanglo]

Query a wire come loose in or around the headshell when you replaced the Speedo cable.

[pxguru]

That sounds quite unfortunate, if it is sparking it is just an engine issue.

Here are a few more things it might be;
1. CDI or loose wiring - sometimes they still spark but just don't start
2. Flywheel spun on the key - often accompanied by backfire
3. Mainseal fell out - Would still start eventually but would run terrible
4. Water in carb - Might fire occasionally but not run

There are probably a few more but too early to think