Get about 3 feet of fuel tubing and add a tee in the fuel line. Put the three feet of tubing to the tee, keep the other end open. Raise the fuel tube above the engine, tape it to a stick or anything to keep it elevated. Start the engine. If the pump regulator is operating correctly and it is adjusted to the low setting the level should be less than 10 inches. High pressure may be near the top of the line. If it is too high and you cannot adjust lower then consider sending back to Conley, though I don't know if they will replace it.

Other than that you may be using too hot or cold of a glow plug. Not sure because I'm not sure how the pump is set up. You may actually be three hundred RPM lean of peak, the pump regulator sometimes does not alway self adjust right away (especially if gummed up with castor) and it may be leaning out as you are adjusting the needle. You can check if the pressure is going up and then down by observing the level in the elevated fuel tubing. Richen the needle up and wait a minute or so to be sure this is not happening.


be aware that I have not done this myself, but have read about this somewhere and am theorizing to some extent.