obinine
03.05.2021 10:33:54
The most common reason an ATV is getting no spark is a bad spark plug, either the wrong plug all together or just not gapped correctly. Or the spark plug just went bad, that happens quite often and it’s normal.
See full version: How To Check For Spark On An ATV: Reasons For No Spark
The most common reason an ATV is getting no spark is a bad spark plug, either the wrong plug all together or just not gapped correctly. Or the spark plug just went bad, that happens quite often and it’s normal.
If you know your spark plug is good and gapped correctly, then you’ll want to check for a loose wire, a bad switch, a bad connection, the ignition coil, or a problem with the stator. Lets go over how to check these one by one.
If you only have one spark plug cap, you will take one multi-meter lead and connect to the spark plug cap and the other to the primary side power connector. here
This test makes sure that the stator isn’t shorting out to the ground. here
Although ATVs are durable, they can still have problems while you are breaking them in. When they do, you will want to ensure that you have picked a company that has a good warranty plan. If you.
The job itself isn’t usually too intense as the stator is typically mounted to the engine in such a way that it is somewhat easy to access. Of course, this will depend on the design of your ATV. [links]
Stators can look quite different depending on the brand of ATV and model, but in general, they consist of an iron core, wire coils, and a cable that allows the stator to be connected to the voltage regulator.
You’ll basically do the same thing listed above, but with the motor running at a set rpm. You’ll need a friend to help you with this! [links]
An engine is considered to misfire when there is not enough electrical energy going to the spark plug to keep it arcing or there is a path- way in the engine for the energy to take that bypasses the plug’s electrodes. Electricity is lazy. It will always take the path of least resistance. If it is easier to go to ground through the insulation on the ignition wire instead of arcing the gap of the plug under high cylinder pressure, it will. When this occurs, that cylinder will not be contributing full power to the crankshaft. The engine will be weak, the unburned fuel will foul the spark plug, and the exhaust will pop. If the mixture is excessively lean, the engine will misfire since the fuel molecules in the intake air are too far apart. When the mixture is lean, the flame cannot expand across the cylinder bore since it requires both fuel and oxygen to accomplish this. more
In like fashion, during throttle movement (transient operation), ignition demand spikes just as the throttle plate is evoked. To diagnose a performance issue expediently, you need to remember that electrical demand is linked to load. more
At idle, the required energy to arc the spark plug is very low since the cylinder pressure is minimal. This is due to the throttle being almost closed, the engine rpm being low, and the fact that there is no load on the engine.
A spark plug on most engines fires from the center electrode to the side electrode. That side electrode is grounded via the plug threads to the cylinder head. If the primary leads to the coil were accidently connected in reverse, the amount of energy the coil could produce would be greatly diminished. Most times, the engine would idle fine, but as soon as any load was applied, it would misfire. more
Re: Yamaha CDI Unit failures [links]
Hi Roger: Check the stater plate(under the flywheel). I've replaced both of mine
on my 9.9s (450 hours). Same symptoms, turns over strong, very weak spark but
won't start. My flywheels were very rusted underneath. Easy to install once you
get the flywheel broken loose, don't drop the flywheel key out of the slot. Unit
wholesale are $185 each. Best/ Jack/ "MOJO" 36078
Hi Chris,
CDI stands for Capactive Discharge Ignition. It is the black box located behind
the wire loom and cover on the port side of the engine. It receives input from
the pulse coil and spark coils (2) located under the flywheel. The spark coils
are mounted on the stator plate along with the charging coils more
Posted by Chet White on July 21, 2003 at 17:31:00:
In Reply to: Re: Yamaha CDI Unit failures posted by Chris Randolph on July 21,
2003 at 11:28:00: [links]
If you are having starting (cranking) problems check A)the 10A fuse at the top
of the wire loom, B)the start solenoid located near the fuel connector, C)The
neutral switch buried under the carb, D) The starter itself [links]
Posted by Bob Johnson on July 15, 2003 at 09:24:00:
In Reply to: Yamaha CDI Unit failures posted by Roger Ford - Kokomo on July 15,
2003 at 04:46:00: