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Jeff Policky
Jeff Policky, Motorcycle Mechanic
Category: Motorcycle
Satisfied Customers: 2425
Experience:  Yamaha Gold, Suzuki Gold, Honda Bronze, Polaris Bronze, BRP
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Yamaha scooter model C3: after turning on, engine light

Customer Question

Yamaha scooter model C3: after turning on, engine light comes on for 2 seconds, then turns off. Engine will crank but will not start
JA: Have you checked the fuel supply? And are all the spark plugs working?
Customer: Fuel OK, engine did start and run briefly first but stopped when lights went out. Now lights come on only briefly
JA: What is the model/year of your motorcycle?
Customer: Yamaha XF50X (C3) 2008, only 1034 miles
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Yes. Checked fuel, since today is very hot (100 deg F) think it may be the heat. However, the scooter had started and run earlier, just won't now. One blogger suggest turning ignition on and off three times quickly, has worked for him!
JA: Anything else you think the mechanic should know?
Customer: No
Submitted: 1 year ago.
Category: Motorcycle
Expert:  RSRBOB replied 1 year ago.

Hi and thank you for your question.

The engine light is acting normally. It comes on for a brief period of time so you can see that the bulb is not burned out. Therefore, that is not related to the no start condition. By the same token, 100 degrees ambient air temperature is not creating a problem for the scooter either.

An engine takes 3 elements to be able to run, spark, fuel and compression. We need to do some diagnostics to figure out which one is missing.

I would like you to pull the spark plug out of the cylinder head and take a look at it. Let me know what it looks like. I am interested to know if it is wet or dry, and what color the tip is.

Now that you have it out, put the spark plug back in the plug cap, lay it on the cylinder head and crank the engine over and look for spark. You should see a fat blue spark. If you don't see any spark or it looks more white than blue, or more closely resembles a sparkler, where the spark is jumping all around, then the plug is fouled and needs to be replaced.

Let me know what you find.