Timing - how far past TDC?
Posted: Sun Apr 03, 2016 11:33 am
Hi,
I wonder if anyone can help me here... I have the marine version of this engine with a magneto, but leaving the mag aside (there is a good spark at 4 plugs) I am trying to get the timing right to start it. At the moment I have set the spark to occur at TDC, but all I get is the occasional misfire and smoke from the carb.
I think that perhaps the spark is coming too early - before the valve is open so the fuel is possibly ignited second time around? Should I advance the timing a bit by rotating the engine past TDC? Any help appreciated!
The magneto delivers a spark at the plug wires well and the spark is good. It mates with the engine timing chain by using a pin in a drilled disc. Basically, I hold the mag at the point just before it is going to fire a spark to #1, move the engine into position and then slot the mag into the disc so the pin goes into one of the holes, bolt it up quick and try to start. So it's not as easy as coil and battery timing to play with!
Thanks,
Nic
I wonder if anyone can help me here... I have the marine version of this engine with a magneto, but leaving the mag aside (there is a good spark at 4 plugs) I am trying to get the timing right to start it. At the moment I have set the spark to occur at TDC, but all I get is the occasional misfire and smoke from the carb.
I think that perhaps the spark is coming too early - before the valve is open so the fuel is possibly ignited second time around? Should I advance the timing a bit by rotating the engine past TDC? Any help appreciated!
The magneto delivers a spark at the plug wires well and the spark is good. It mates with the engine timing chain by using a pin in a drilled disc. Basically, I hold the mag at the point just before it is going to fire a spark to #1, move the engine into position and then slot the mag into the disc so the pin goes into one of the holes, bolt it up quick and try to start. So it's not as easy as coil and battery timing to play with!
Thanks,
Nic
