Right, back on track. So just been playing - and for giggles and my own sanity decided to recurve the dizzy to something less extreme and see what that produced.
So I change the advance stop bushing to a 21deg total, set the curve springs to light (which should give me full advance at 34) and the initial to 13.
Timed her up. Runs nice. 13 at idle, 34 at 3K.
Now, according to the manual, the vac can should pull in 'up to 10 deg', so in theory even if it went nuts it would only pull to 23; enough to run OK.
Connected up the vac. Idle stays the same, advance stays at 13 on the gun. Touch the throttle, and BANG ! BANG! Pop Splutter ! Bang cough. die. Advances off the scale when you touch the loud pedal.
What I cant establish (cause I cant get her to run long enough ) is just how far advanced we are going here. I may back it right off to silly low and see if I can get a reading on it.
At the moment I am thinking vac can isn't doing what it should, or there is a stop missing somewhere.
Yes, I know, I know. Don't need to run vac - BUT I don't want it smelling like this either. And for my own sanity and learning I want to know why this vac aint doing it. Most mechanics I have spoken to don't seem to know much about it when it comes down to it - usually they just connect it up and that's that.
Anyway, as promised and for future generations I will let you all know how I get on.
Morgan.
PS - Incidently, the 'sweet' spot for the engine doesn't seem to be 13, the idle increases as the advance gets higher. I have not yet found the spot where the 'rate of idle increase lessens'. I am tuning my ears. But it does seem remarkably tolerant and will run on just about any setting you like. Apart from with the vac on, obviously...
PPS - Talking of tuning my ears, 3,000rpm with your head under the bonnet rattles the old grey matter around doesn't it ?
