Prop Starting A Volkswagon Engine

[CHARLES DEBOER]

Could someone point me to or give me information on prop starting my XL.  I have never prop started an VW engine with a magneto before.  Any suggestions??

[joecnc2006]

Here is a quickvideo in the beginning from Less, but I'm sure i saw one showing the proccess.

[Dan_]

Could someone point me to or give me information on prop starting my XL.  I have never prop started an VW engine with a magneto before.  Any suggestions??

Always assume the mag is hot.  The mag "switch" grounds the P-lead.  In other words if the wire is lose, broken or the switch is bad the mag is hot and the plane will still fly.

If a cylinder is coming up on compression and has had a smell of gas it will hit if the mag is hot,  this is why the G.A. practice is to kill the engine by pulling the mixture control to lean cut off.  I like to cut the fuel off, run it up to about 1500 then pull the mixture to LCO.  This insures the cylinders are dry and will not start if the P leads have lost ground.  

Also it takes the needle off the seat in the carb until the fuel petcock is turned back on...  It is just good practice to put your plane away with only oil in the cylinders and makes moving the prop that much safer.  The petcock going off early is just my habit.  

Here is another video...

[CHARLES DEBOER]

Could someone point me to or give me information on prop starting my XL.  I have never prop started an VW engine with a magneto before.  Any suggestions??

Are there any peculiarities when pouring fuel into the tank and priming the carbs?  I have not put gas in the tank since testing for leaks.  It has been dry since that test.  I imagine there might be air pressure in the fuel line going to the carbs until the float bowls fill with fuel.


Always assume the mag is hot.  The mag "switch" grounds the P-lead.  In other words if the wire is lose, broken or the switch is bad the mag is hot and the plane will still fly.

If a cylinder is coming up on compression and has had a smell of gas it will hit if the mag is hot,  this is why the G.A. practice is to kill the engine by pulling the mixture control to lean cut off.  I like to cut the fuel off, run it up to about 1500 then pull the mixture to LCO.  This insures the cylinders are dry and will not start if the P leads have lost ground.  

Also it takes the needle off the seat in the carb until the fuel petcock is turned back on...  It is just good practice to put your plane away with only oil in the cylinders and makes moving the prop that much safer.  The petcock going off early is just my habit.  

Here is another video...

[Dan_]

Are there any peculiarities when pouring fuel into the tank and priming the carbs?  I have not put gas in the tank since testing for leaks.  It has been dry since that test.  I imagine there might be air pressure in the fuel line going to the carbs until the float bowls fill with fuel.

You might want to clip an extra ground off an on to the p-lead until you get more comfortable around your test set up.  

If your carb vents are clear there should not be much drama getting the float bowls full.

Consider running the bowls dry at the end of your test runs and note how long it takes so you can perhaps estimate when to cut the fuel when taxiing in at the end of your flights...

[CHARLES DEBOER]

Are there any peculiarities when pouring fuel into the tank and priming the carbs?  I have not put gas in the tank since testing for leaks.  It has been dry since that test.  I imagine there might be air pressure in the fuel line going to the carbs until the float bowls fill with fuel.

You might want to clip an extra ground off an on to the p-lead until you get more comfortable around your test set up.  

If your carb vents are clear there should not be much drama getting the float bowls full.

Consider running the bowls dry at the end of your test runs and note how long it takes so you can perhaps estimate when to cut the fuel when taxiing in at the end of your flights...

I have a single pole, single throw switch wired to the mag.  One of the terminal comes off the mag case.  I assumed that was the ground so I ran two wires off that connection.  One to the switch and one to the engine case as a ground.  The other terminal I assumed was the hot terminal or the P-Lead. I ran a wire from that to the other connection of the switch.  IS THIS CORRECT?   I do not have the wires connected to plugs so as not to accidentally make the engine hot.  No fuel in tank or carbs.

[Dan_]

I have a single pole, single throw switch wired to the mag.  One of the terminal comes off the mag case.  I assumed that was the ground so I ran two wires off that connection.  One to the switch and one to the engine case as a ground.  The other terminal I assumed was the hot terminal or the P-Lead. I ran a wire from that to the other connection of the switch.  IS THIS CORRECT?   I do not have the wires connected to plugs so as not to accidentally make the engine hot.  No fuel in tank or carbs.

As long as the prop is not moved through a compression stroke it won't hit...  You should be hearing the impulse coupling snapping.

Use a reliable switch to ground the center of the P-lead to the shield of the P-lead.


P- lead is short for primary winding.  Mags generate their own juice.  P-lead is not the "hot" you would send batt. current to the coil like in the car.  If both ends of the primary winding in the mag coil are not grounded by the switch the mag will fire the plugs.






A link to a pdf on switches and a video....

[cluttonfred]

This might be a good place to start...

http://cluttonfred.info/post/142344541205/thoughts-on-60-years-of-hand-propping-fred#.V9eVCmWeqrU