All this talk of weak spark got me thinking again about my 20B. It has the stock CAS. I have found that the spark is weak and sometimes intermittent when cranking.  When I noted this, I was sure something was wrong.  I then checked using the Mode 8, and the spark was great. It would start and run, so I forgot about it. The engine always started and runs fine, but I have noticed more recently on cold mornings (meaning about 40F here in SoCal) that the starting was a little more hesitant, and would fire intermittently for a bit before getting going.

 

I recall when we were checking timing on the dyno, it would not fire the timing light consistently – figured it was the light.  On recent flights, on two occasions, after steady cruise for ½ hour or so; there was a very short duration power sag; just a second or two and then back to normal.  No roughness; just some power loss that gets your attention, and then it’s OK.  I’m burning unleaded mogas, so shouldn’t be the famous S.A.G. others have experienced.  I have no explanation.

 

These things, taken together, make me wonder if I’m really getting the strong spark I should be getting.  I know that during cranking it is barely enough to fire the plugs.  I haven’t checked it when running cuz it’s a little difficult to hold a wire off and see how far the spark will jump when that prop is going right there.  But I guess I need to make a check of that.

 

What sort of cranking spark should be expected? Other ideas on what to check? Is it something about the EC2 and the CAS?

 

Al

 

 

 

 

 

Subject: [FlyRotary] flooding