exhast stroke intake stroke

[andythespreeowner]

I think i found out why my 20$ spree wont start,hows this, i have been trying to start it with a 14mm socket on the flywheel going clockwise.Ive been told this is the ex. stroke.Is the intake stroke counter clockwise.If so ill bet im not the only bonehead to make this mistake.Too late to try ive taken the top end off waiting for some new rings.SO YOU NEED MORE THAN SPARK,GAS,AND COMP. YOU NEED TO TURN THE ENGINE THE RIGHTWAY RIGHT?

[Bear45-70]

You have no clue about how a two stroke motor functions so stop trying to figure it out with wrong logic! Oh and quit listening to morons!

[devenex]

The direction that the crank spins will not affect the timing. The piston will not know the difference since it is still just moving up and down. I suppose I should also add that while the motor CAN be started the wrong way its probably not a good idea

Also rumor has it wheelman started a motor the wrong way once!

[Wheelman-111]

Greetings:

Nope, not me! I've never started a Spree, though I wouldn't put it past me to make the same error.

In point of fact, the Ignition Module does know which way the engine is spinning. Spark timing is such that spark occurs a few degrees before Top Dead Center, by means of the magnetic ignition pickup. If the engine is spinning "backwards", the spark won't occur until a few degrees After. If it starts at all this way, it won't run very well.

[wiguy05]

This guy and his scooter have been a slow train wreck so far. Epic!

[mousewheels]

The direction that the crank spins will not affect the timing

-- For Intake/Exhaust port timing the above is correct. The direction the crank spins can impact ignition timing - unless the spark trigger coil is placed at TDC, and we can show it's not set to TDC... How much? A good topic to pursue.

-- Rotation direction --
The whole rotation direction, clues, and general discussion value is always interesting. Here's some info:

• I am easily confused when folks say an engine rotates CW or CCW. Some are thinking the output (pulley side), others, the flywheel. But it's easy to get to 'know'
• The shape of the fan blades is pretty interesting - and one time we caught a Mechanical Eng (grin) misinterpreting how a fan works. The curve looks incorrect, but is sound engineering
• Spree's have a single gear reduction trans, so the engine must rotate opposite the wheel rotation

Put the above into some crude diagrams gives us this:
Honestly, I need to make a better diagram, but believe you can get your rotation question answered from the two pics.

Spree_Fan_Rotation_Direction.JPG (16.78 KiB) Viewed 3934 times

At the transmission, the output shaft must rotate CCW so that the tire will drive the scooter 'forwards'
If the output side is rotating CW, and you pull the flywheel cover, the engine is rotating CCW from that perspective...

Spree_Trans_Rotation.JPG (12.58 KiB) Viewed 3934 times

[Bear45-70]

Greetings:

Nope, not me! I've never started a Spree, though I wouldn't put it past me to make the same error.

In point of fact, the Ignition Module does know which way the engine is spinning. Spark timing is such that spark occurs a few degrees before Top Dead Center, by means of the magnetic ignition pickup. If the engine is spinning "backwards", the spark won't occur until a few degrees After. If it starts at all this way, it won't run very well.

No, the module does not know or care what direction the engine is turning. All it knows is that the pulse generator (I prefer pickup) says spark now. Because of the physical location of the pickup the motor will only run one way now. Move the pick to the other side of TDC the same amount as it is stock (or add a second pickup and switch between them) and the engine will happily run the other way.

Back in the late 1950's Mercury Marine found they did not have a shiftable gearcase design that would stand up to the 60 and 70 horsepower power heads they had. So they rigged the throttle linkage, which also moves the timing so when you pulled the lever into reverse and cranked the reverseable starter motor (a double bendix affair) the other direction the motor ran fine. Two strokes don't really care which direction you run them.

[motormike]

Golf carts with 2-stroke engine are also designed to run backwards to achieve reverse.......'74 Harley-Davidson for one...........

[reynoldston]

Seeing you are trying to start it with a socket could it be that it is not turning over fast enough to start?

[Bear45-70]

Seeing you are trying to start it with a socket could it be that it is not turning over fast enough to start?

If the drill is turning the engine over at all, it is fast enough.

[reynoldston]

I guess I missed the drill part, that sure would be fast enough. That sure must be one strong drill.

[Bear45-70]

I guess I missed the drill part, that sure would be fast enough. That sure must be one strong drill.

A 1/2 drill motor is probably at least 5 times stronger than any scooter starter motor.