Modern Vespa

After going around and around with starter problems with my ET2 and ET4 I would like to share my limited knowledge with the idea that it will help someone. Note that is only electrical diagnostics not engine problems.

Basic Starting Problem:

The engine will turn over slowly but not fast enough to start. This is usually a battery problem. Pull the battery, check the voltage with a volt meter. It should read at or above 12 volts. If it shows 12 volts and cranks slowly then charge it and try again. Still turns over slowly then jump it with a car battery. If it starts right up replace the battery. If it is still sluggish then check all the wires going to and from the starter motor to the battery. Clean the connections and try again. If it still doesn't start you may have a starter motor problem.

Starter motor Problem:

Starter motors never fail? Wrong. Here is the method I used to trouble shoot a starter motor problem. First listen for the starter relay to click when you try and start the engine if the starter motor does not turn over. If you hear the click when you press the starter button then check the voltage at the starter motor. It should read the same as the battery voltage. If there is no voltage present or it reads lower than the battery then you may have a bad connection between the starter relay and the starter motor or a short in the starter motor.. Clean the connections, ground wire too, and try again. If the voltage is 12 volts, when you hit the starter button, then there is probably a problem with the starter motor. You can jump directly from the battery to the starter motor with jumper cables. Connect one to the starter motor and the other to the starter motor case. If it still doesn't turn then you need to remove the starter and test it.

The way I tested the starter motor after removing it was to jump it with battery cables. In my case sometimes it turned and sometimes it didn't. Now you have a choice to make, buy a new one from a dealer, around $300, or try and get the old one fixed. In my case I took mine to an auto electric repair shop and they rebuilt it for about $18 while I waited. Of course I live in Mexico and things cost a little less here. After the rebuild, new brushes and clean commutator, it worked like a new one when I reinstalled it.

Starter Relay Problems:

Another problem that I had was a bad starter relay. I had a dead battery. When I replaced the battery the scooter tried to start once I attached the new battery leads even with the ignition switch off. If I turned the switch on the scooter would start but the starter motor would keep running until I disconnected the battery. When the battery was disconnected the scooter would run just fine. The problem was solved by installing a new starter relay. By the way the relay for the ET2 is the same as the ET4 but the starter motors are different.

I know that this is a long posting but I hope that it will help someone diagnose some starting problems that we all will have sooner or later. Would be glad to answer any questions that you might have, just ask or come down for a visit and let's ride Puerto Vallarta. You get the ET2, the wife will not ride it.......

+1

Good post.

Good entry for the Wiki.