David,
It most probably isn't the timing at all, in fact, if it is running you could almost guarantee it isn't the problem.
If it is supposed to run faster, then try moving the flame a tiny amount, first along the engine axis, and if that doesn't do it then towards and out. I am talking real tiny amounts. First off, felt tip where you started from, so that you can get it back in the same position, then it will be 1/2mm steps from then on.
If there is no change, then that is what the engine runs at.
You must have seen how slow mine runs at, and no amount of adjusting will get it to run any faster.
That is around 400 RPM, and the power output is actually just enough to keep itself running, if one flame goes out, you've had your lot, it stops.
That is why they were never successful commercially, too much fuel in, too little power out.
John