I tested quiet a few used injectors,and nozzles. Pretty much all of them leak. Some the pintles were also stuck. Lapping the needles with polish has debatable results . I used to think a little leak at the tip was ok,since they almost all do this. I have since changed my mind,and think it might be the number one cause of engine failure. Brand new china marine nozzles will also leak. It seems new Bosch nozzles are kinda rare,and Bosch marine nozzles even more rare. I thought that the main difference between the 304 turbo nozzle and the 311 marine nozzle was just the cut off tip. This is not the main difference,the marine nozzle has .010 more travel. Hole sizes are also identical. I believe the extended tip on the turbo nozzles is just there in case of carbon build up,it will not really restrict fuel. The gap between the needle and seat,and also the flat side of the pintle,limit the amount of fuel. For now I'm going to probably use some new stock injectors. Later I want to either increase the travel on 304 nozzles,or get some Monark or Bosio nozzles for Mercedes and VW applications. Does any one know if they would fit ? If not I will just buy one and check it out . I also believe that the reason people have trouble with marine injectors,is probably the nozzles are poor quality,and leak,or the tips carbon up ,because of the shortened needle tip.