The fixed jets were supposed to keep the constantly fiddling ignorant motor owner from constantly mis-adjusting his motor. I believe they introduced almost as many problems as they fixed. You could no longer adjust for humidity, boat load or altitude. I have put an adjustable needle valve in every fixed jet motor I intended to run. A tiny bit of crud can lean out a fixed jet enough to cause damage under load. Likewise overly aggressive cleaning (using a small file to clean out an oriface) can cause a loss of power and an increase in smoke and fuel use. Then again, that’s just my personal opinion . . . 😆
