150CC Jon way no start By gordian79 (Read 1,142 times)

[gordian79]

I have a no start situation.I have spark but it doesn't seem strong and it sometimes goes away.I swapped out the following parts into a working scooter and the other scooter started.cdi,stator,coil,spark plug,starter solenoid.I have also done everything on the no spark diagnosis pdf file everything checked out fine.The only one that didn't check out was on page 6 where it says to "test kill switch itself".this scooter cranks with kill switch in either position.In fact it cranks with kill switch wires unplugged.it also cranks with side stand in the down position.

thanks

[Alleyoop]

Have you checked if gas is getting sucked into the Manifold.
Take the Vacumm Hose Off the MANIFOLD and squirt some gas into the nipple and put the Vacumm hose back on. Crank it and see if it wants to start it may start and die.
If it starts or Attempts to start then you know It is a Fuel Delivery Problem.
Alleyoop

[gordian79]

Spark plug is wet with fuel.I even opened up fuel drain valve leaked fuel so there's fuel in the bowl.

[Bashan]

Well Alley's test ruled out fuel issues. Hmmmmm....Is the spark yellowish or orange looking? It should be bright blue. If you've swapped out all of those parts and you're sure they're functioning properly you have a partial short somewhere. You'll have to start tracing and checking wires.You may have a loose ground wire also, check the main ground on the frame. Also, do you know how to check continuity with your multimeter? You can check the grounds by touching one probe on a green wire and the other on a bare spot on the frame. You'll get a tone if the wire is good. You can do this with all the wires if you know where they start and end up. Check all of the little pins on your CDI and check the coil connections. Just one little bad connection can cause a spark problem. Rich

[Alleyoop]

But here is the thing, even if there is Fuel in the BOWL does not mean the fuel is being sucked into the intake. If your Fuel Ratio screw is to closed or your Butterfly is closed no fuel will get sucked into the intake mainifold. But since you just said that your Plug is wet then I suspect a very weak spark or no spark.

If you have a Spare Spark Plug take coil off the Spark Plug in the motor and stick the Spare Spark Plug into the Coil Boot and GROUND it to the ENGINE and see if it sparks. If it doesn't then take it and Ground it to the FRAME and see if it sparks.

Many times the Engine GROUND to the FRAME is not good and It will spark on the Frame BUT NOT when in the Motor. If that is the case then Check the Ground Wire From the ENGINE To the Frame.
Alleyoop

[gordian79]

I tested the grounds and they are good.one thing I noticed is that the running scooter has 3 ground wires to the frame right below valve cover and the non running one had none.I added a ground from valve cover to frame.I'm assuming the other grounds the running scooter has are the starter and the battery grounds.One thing that's weird is that it cranks with kill switch in either position it even cranks with wires unplugged from switch.The spark I get is very weak I don't think it's enough to fire up.

[Alleyoop]

Some will crank with the kill switch OFF mine does as well. When I change the oil I put the kill switch on so it will not start and crank it to get more oil out.

Have you tried the COIL from the running scoot as well as the CDI from the running scoot.
I would first take the Coil off the Other Scoot and try it. If Still a weak Spark then take the CDI from the other Scoot and try it. If still a weak spark then it most likely is your Stator.
Alleyoop

[gordian79]

I've tried coil,cdi and stator from running scoot and it still doesn't start.I've also put the coil,cdi and stator from non running scoot onto running scoot and it fires right up.

[Alleyoop]

OK, unplug the Kill Switch from the CDI.

Did yOU do any work on the Scoot or layed it down or just one day it was running and the next no spark?
Alleyoop

[gordian79]

I bought with no start condition for cheap so I can swap out engine into my running scoot.the running scoot has 3700 miles and it's making a knocking sound.yes scoot was dropped.I want to start this motor tonmake sure it's good. So unplug kill switch from cdi and attempt to start it?

[Alleyoop]

Yes, take the Killwire Off the CDI and attempt to start it. Since you layed it down, do you know if it has a kill sensor in case the scoot goes on its side? Some scoots have safety switchs for that purpose to kill the engine if it is on its side.

have you checked the PICK UP COIL and the connections from it.
Alleyoop

[gordian79]

Where would that safety switch be?

[ce]

Might as well adjust the valves before you go any further. If the exhaust valve is closed or a rocker arm is broke, it'll never start.

[gordian79]

Adjusted valves already they at .004

[Alleyoop]

They can put those things just about anywhere, some are square some are a little cylinder. They ususally put them under the seat or by the battery etc..

But first take the Kill Wire OFF the CDI and see if it wants to FIRE. We know it will crank but does not attempt to fire due to NO Spark.

What side did it go down on, the CVT side or the Muffler Side, Did it hit anything by the Flywheel or motor. It could be something just got unplugged as well but I think you would have found it already since you changed out parts.

The only other thing I can think of is the PICK UP COIL, You can check it just by taking the Fan Cover off and see if it looks ok in the right position and connected.
Alleyoop