Timing a f12

[handcrank]

Can someone give me a step by step process for timing an f12 It's been sitting for several years. Magnito has a hot spark. Points set at o13.any help appreciated.

 

[DeltaRed]

If the mag is still on it it should already be timed.Lever all the way up is stop/retard.Down is full advance. Just set the lever about mid range and try it.

 

[DeltaRed]

If the mag is off,put #1cyl at TDC.then set the rotor to #1 plug wire.line up the correct holes on the coupler.

 

[used red MN]

Just to clarify number 1 cylinder has to be on TDC of the compression, stroke not the exhaust stroke.

 

[rustred]

sounds as if you are verifying that it is timed correctly? crank engine as slow as you can with the advance lever off the stop postion till you hear the impulse trip and see the spark jump the gap, with #1 spark plug out. then you check where your timing marks are sitting. if there are out a bit adjust with the 2 1/4 bolts in the coupling. but make sure you are hardly moving when it trips so that you dont be turning it past the trip.

 

[handcrank]

I had the mag on the bench and spun it and it had good spark. I have been trying to get the number one cylinder on top dead center.with my thumb in the number one spark plug hole. I can't feel any outward pressure when I turn it over. Could this be a stuck valve?I'm in my eighties trying to do this by myself,so mistakes will be made.Thanks for any help

 

[rustred]

well to be absolutly correct with no maybe's.... remove valve cover and look at the valve rockers. when # 1 cyl.is on compression those 2 rockers will be loose meaning set to spec. its running mate #4 cyl's valves will be tight. pretty fool proof. plus its a good idea to set all the valves at this time.

 

[handcrank]

What is the correct setting for the valves? This is all new to me, trying to to go step by step. Just took the valve cover off tonight, will check the valves tomorrow.

 

[Oldiron29]

.013 valve lash will be a little tight for a engine with some wear. I would go to .o15 two thousands over to alow for expansion when hot.
Also I could never read the timing marks on the flywheel through the little hole, So I was told when the mag clicks the front crack pin on the engine crack shaft should be horizontal this is true when piston is TDC. You can use this when setting valves start at TDC #1 and set
one turn crank half turn till pin is horizontal again than three again than 4 and again two. Watching the valves both intake and exhaust will be closed on TDC when you adjust them.